Why did the number of Nazis in the Bundestag increase significantly in 1953?

End of WW2 era and denazification, start of Cold War era

It must be said that among vast majority of (Western) German population after the WW2, there was a general concusses it would be best to forget WW2, or at least least set it aside, and concentrate on present circumstances and attempts to improve them. Overall, electorate in first elections in 1949 and 1953 was mostly divided between Christian-democrats and social-democrats. Despite sometimes vast differences in economic politics (capitalism versus some kind of socialism), both of these major parties accepted that Germany is now part of Western world (parliamentary democracies) and tries to align themselves with its values, as opposed to one-party systems like it was in Third Reich, or is now in Soviet Union and satellites.

This goes especially for CDU/CSU which was part of ruling coalition at this time and gave chancellor (Konrad Adenauer). While social-democrats were sometimes flirting with idea of Germany being neutral between USA and USSR, Christian-democrats were staunchly pro-American and this resonated well with the voters. Adenauer was firmly dedicated to idea of integrating Germany into Atlantic structures (which would become NATO) and Western European structures (which would become EU) . His idea was that Germany is now becoming a member of a new coalition of states and hopefully player in a winning team. On the other hand, he and his government carefully skirted around WW2 topics, in principle admitting German defeat and guilt, but also demanding German unification (with East Germany ) and sometimes giving a hint that they would like return to German borders of 1937. This last idea was borderline controversial, as Germany was filled with those expelled mostly from Eastern Europe, but also goes somewhat contrary to decisions made by victorious countries after the war. In any case, Adenauer and his coalition were fighting for refugee/expellee vote, but were smart enough not to hint any kind of offensive war to achieve that. This in turn was well accepted by war weary German population.

Of course, German whishes were one thing, but decisions of WW2 victors were something else. Overall pattern was that countries more devastated by German aggression during the war tended to push for harsher punishment (vengeance), while those that avoided said devastation (US above others) relatively quickly moved from sanctioning to helping. Indeed, Americans in 1945 started with JCS 1067 (light version of Morgenthau "starvation" Plan), but already in 1948 Germany was included into Marshall Plan. Main Nuremberg trials ended in 1946, and subsequent in 1948. There were war crimes trials after that, but to accused individuals and not certain groups within German state. Policy of denazification (which prevented many former National-Socialist from participating in public life of Germany) met similar fate. While starting grandiosely in 1945-46, it petered out by 1948, and was abolished completely in 1951. It must be said that one of the selling points of CDU/CSU coalition was exactly "quick and fair" denazification. They did not push for complete abolishment of it, but wanted to end it quickly which matched wishes of general public.

Overall, first government of Konrad Adenauer (1949-1953) is considered as a huge success, not only economically but also politically. Adenauer among other things managed to secure rearmament of Germany, and US/British support for Himmerod memorandum, which "cleared the honor" of German professional soldiers (officers) and commuted sentences of those sentenced for war crimes by Western Allies. West Germany became part of anti-communist block in Europe, and by 1953 elections large part of immediate (WW2) past was put behind. Ordinary German citizens were now secure that no one would ask much question what did they do during the war, but also that German state would recognize their diplomas, pension rights and other benefits and privileges earned during the period of Third Reich. With this "clean slate" situation, many former NSDAP members, no longer under denazification restrictions, openly participated in political life and were elected on various lists. Note that they did not have unified political program, i.e. they belonged both to the left and right of political spectrum. As a rule, those most successful among them skillfully differentiated themselves from National-Socialist ideology and adapted to new circumstances.

Main reasons, within the frame of numbers given:

• with every day after Nuremberg trials, having been a nazi became less and less of a problem for filling prominent positions in West-German society and politics
• 1953 election became polarised in topics over East-West foreign policy and alliances, giving the staunchest anti-communists a certain edge
• most important: a new party entered parliament which favoured (ex?-)nazis even more than the other parties

The actual number given as "45" former party members on the Wikipedia page is not reliable, but likely higher. For any given tim eperiod.

On a state level, the 1953 elections were the first elections for the West-Germans in which they could form their opinion not only on local performances, superficial sympathy and more important promises before an election. It was the first election in which the actual deeds in parliament on a federal level could be judged: past performances as a vague predictor for future actions.

Almost all parties in 1953 had 'their nazis' as members, with a very notable influence in the government parties of CDU, FDP. Chancellor Adenauer was known to justify this with 'if you don't have clean water, you use dirty …'. It was just too inconvenient at the time to let really prominent or 'top' nazis too much to the forefront of the public eye. Meaning that an all too prominent role as a leading figure for a nazi was now a bit more complicated. Behind the scenes, things were running smoothly again for former party members…

With one exception that is quite relevant here. The first election didn't know one party that really had all, the All-German Bloc, League of Expellees and Deprived of Rights (GB/BHE). The name already says 'those deprived of rights', this being an allusion to no longer be allowed to dominantly scream bollocks about 'master race' in public and some of them being indeed imprisoned, otherwise sanctioned.

The election in 1953 was predominantly about Adenauer's policy, mainly in foreign policy and thus about unquestioning Western course and allegiance for the West-German state. Which would mean 'sacrificing' unified Germany, eastern possessions etc. A pill quite hard to swallow for really many, who then had to look for other options, even if they were otherwise right-wing conservative, post-fascist in leaning: A more unification oriented Social-Democrat opposition was too left wing, to not even think of the communists who did strive for a unified communist Germany then.

Many found the GB/BHE the most attractive option. It had a not so secret name inviting former comrades back into power, promised even more than the governing conservatives to never let got of any eastern German territories, to rehabilitate 'the rights' of 'the right'. This party, founded in 1950, even had a chairman with the following features:

• participant in the Beer-Hall-Putsch (minor role as young student, but 4 days in prison as result)
• member of the NSDAP since 1933 (No: 2.331.552)
• member of the SA since 1933
• part of Gauleiter administration, responsible for Germanisation-policy in Poland, leader of "Arbeitsgemeinschaft zur Erforschung der bolschewistischen Weltgefahr im Einsatzstab Reichsleiter Rosenberg" (Working Group for the Study of the Bolshevik World Danger in the Operational Staff of Reichsleiter Rosenberg)
• organiser of a Putsch in 1934 in Memel area to turn that strip into Nazi territory
• a fierce proponent of ethnic cleansing in Poland, even more racist than many other nazis
• convicted 1960 in East-Berlin in absentia for war crimes and crimes against humanity as a participant in a death squadron in Ukraine

This list goes on. He had some internal trouble due to power struggle competition with the SS, but he was clearly a guilt-laden top-nazi. Regarded as and respected as a Mitläufer in West-Germany.

This man, Theodor Oberländer, was elected to parliament in 1953. Together with his party, quite full of not-so-hidden nazis, bolsteríng the number of 'too many nazis still at helm'. But if that wasn't enough, his post-fascist nazi party joined Adenauer's government!

Oberländer became head of the Federal Ministry of Displaced Persons, Refugees and War Victims a position in which he could show off his 'expertise' on eastern affairs, and showcase the demands to reinstate Germany within the borders of 1937.

In order to verify this explanation for 'the big jump' in the numbers of former nazi party members now in parliament, on might also just count BG/BHE members in the Wikipedia list, watching out for 'Bundestag' and '1953'. Perhaps even just comparing and following up on the info mostly available on List of members of the West German Deutschen Bundestages (2. election period).

Note also that the elections results: the more open fascist DRP lost all of their five seats, while the GB/BHE entered fresh with 27 seats from the start.

This 'trend' became quite visible when in 1950 the new GB/BHE entered for example the state parliament of Schleswig-Holstein: a genuine member of the antifascist resistance, Paul Pagel was to be elected prime minister but was blocked by the second strongest party, the GB/BHE. That party campaigned most strongly on an 'end denazifaction' claim, but was only the loudest voice for that, with the other parties mainly agreeing on that.

Note that Wikipedia uses an election campaign poster from 1949 and the FDP to illustrate the topic. The GB/BHE was a little more traditional in visual aesthetics:

For the 1953 campaign:

as well as:

For the 1957 campaign:

With some arguing for a Germany within its 1937 borders, the GB/BHE still was most aggressively advertising its/'the German' claim to Sudetenland:

Instead of Pagel, the nazi Walter Bartram (No 3.749.168, now CDU) became prime minister in 1950 Schleswig-Holstein. With Pagel as one of his ministers, then interior affairs. But since Pagel was the only member of that cabinet without a nazi past, he coined the term "renazification" for the whole process. Almost needless to emphasise now, Bartram then went on to the federal parliament Bundestag for the CDU, from 1952 to 1957.

To repeat and emphasise what's perhaps only inferable from the above: the GB/BHE was not the only party delegating nazis into parliament and other places of power at that time. But the Wikipedia entry summarises correctly:

The BHE played a central role in the termination of denazification and the professional reintegration of former National Socialists who had encountered career problems because of their past. It was a rallying point for anti-communist and revanchist forces in the young Federal Republic. Its ranks included many former NSDAP members, among them Kraft and Oberländer. Kraft therefore made a point of stating as early as 1952 that the BHE was the party "also of former Nazis, but not of those who are still Nazis today." […]

Of the party's members, senior positions included many former members of the NSDAP, including convicted war criminals.

With the part about 'not of those who are still Nazis today' subject to definition issues and some fruitless debate about that. Kraft himself joined the SS in 1939, the NSDAP in 1943.

To drive it home: the first two parliamentary group leaders of GB/BHE after 1953 were:

• Horst Haasler, NSDAP since 37/38, later joined CDU
• Karl Mocker, first Sudeten German Party, then NSDAP, later GDP

The Bundestag itself remembers this period as 'Back on the World Stage'. A less (prominently) accessible, yet official and not very flattering overview is found in Deutscher Bundestag Drucksache 17/8134 17. Wahlperiode 14. 12. 2011, "Antwort der Bundesregierung auf die Große Anfrage der Abgeordneten Jan Korte, Sevim Dagdelen, Ulla Jelpke, weiterer Abgeordneter und der Fraktion DIE LINKE. – Drucksache 17/4126 – Umgang mit der NS-Vergangenheit (PDF). It also highlights the even much bigger reintegration of nazi civil servants into their former positions, mainly under the 131 law of 1951.

A severely deficient but English language journalistic approach to that document:

After World War II, West Germany rapidly made the transition from murderous dictatorship to model democracy. Or did it? New documents reveal just how many officials from the Nazi regime found new jobs in Bonn. A surprising number were chosen for senior government positions.

— Ralf Beste et al: "The Role Ex-Nazis Played in Early West Germany", Der Spiegel, 06.03.2012.

For a summary of the main topics and dynamics in that election:

— Mathias Friedel: "Bundestagswahl 1953" (p112), in: Nikolaus Jackob (ed): "Wahlkämpfe in Deutschland. Fallstudien zur Wahlkampfkommunikation 1912 – 2005", VS Verlag für Sozialwissenschaften: Wiesbaden, 2007.

A short 'tip of the iceberg' narrative summary of nazis in politics:

— Wolfgang Michal: "Nazis im Bundestag", 20. Sep 2017.

Important final caveat:

The Wikipedia page on Liste ehemaliger NSDAP-Mitglieder, die nach Mai 1945 politisch tätig waren is explicitly mentioned as unreliable in the following publication. For once, it is incomplete, therefore even just counting the 'known party members' and making a graph from that underestimates the extent. Second, a 'nazi' might be in the SS, the SA or otherwise involved in extermination and other policies, but not be a formal party member. Since the question is explicitly exclusively about 'former party members in parliament in 1953', a focus on that subgroup is still lackinga robust scholarly study of the problem:

The National Socialist past of the members of the first to the fifth German Bundestag has not yet been systematically researched, nor has that of the Bundestag staff. There are only isolated preliminary studies on the National Socialist affiliations of members of the German Bundestag, which, however, are of limited significance in view of the total number of members of the Bundestag. […]

The aforementioned gaps in the documentation of the life phases during the National Socialist era cannot be compensated for with the help of other works either. Neither — the online publication "M.d.B. Die Volksvertretung 1946-1972" published by the Commission for the History of Parliamentarism and Political Parties, which documents the curricula vitae of MPs in a similar way to the Biographical Handbook, nor the compilation "List of former NSDAP members who were politically active after May 1945" in Wikipedia — can lay claim to complete coverage of the relevant biographical features or NSDAP membership of members of the Bundestag, characterized by a consistent systematic approach.

— Wissenschaftliche Dienste de Bundestages: "Sachstand Zur Forschungslage bezüglich der nationalsozialistischen Vergangenheit von Bundestagsabgeordneten und Bundestagsmitarbeitern", Deutscher Bundestag WD 1 - 3000 – 045/18, 2018. (PDF)

That means the explanations above only cover those former members most well known, not all of them. Some have succeeded to this day to hide their tracks.

I edited this in response to the comments. You can check the history for the first answer.

I consider this an anomaly in the first data point of the graphic. Note that the four bars represent one four-year term, changes within one term are due to deaths or resignations.

• Germany had many Nazis in key positions after the World War.
  This applies to both East and West Germany, but more in the West. Senior officials of the Nazi regime could continue their careers after the war, and it took half a century (when many were safely dead) before the German society took a closer look at their brown stains. For instance, many senior judges remained in their position. Similar in the government administration and the economy.

• The Wikipedia page defines being a Nazi as party membership.
  I have not checked every entry, but the list contains people who were young adults when they joined the party, and others who were 17 years old at the fall of the Third Reich. It omits people who were implicated for organizing concentration camp labor, yet did not join the Nazi party. To me the list is interesting reading but no suitable basis for statistical analysis without a case-by-case judgement. Quite a few claimed later that they were "forced" to join to maintain or start their careers under Nazi rule. Some of that are weak excuses, some are more credible.
  So I do not see the strong correlation between Nazi ideology and party membership which the OP assumes. Read about the Gleichschaltung, the nazification of Germany after 1933, and the number of organizations other than the party implicated in the nazi ideology. Listing former HJ members would yield even greater percentages.

• German society was in upheaval in 1949
  The question seems to assume that it would be natural to re-elect incumbents in 1953, and that therefore the increase in numbers signified a political change. Denazification was still ongoing when the first West German parliament was formed. Parties still required an Allied license in 1949. This ended in 1950, leading to the formation of more splinter parties.