score:34
When a war starts, the diplomats lock down the embassy and leave through a neutral country. They are neither molested nor harassed, and their diplomatic immunity is not disputed. The embassy building and the property therein is taken care of by the neutral country representing the interests of the belligerent (or some other arrangements may be made).
The major point is that both belligerent nations recognize that the war is a temporary affair in their long-term relationships and that a decent treatment of diplomats serves both sides.
One exception I know of is the treatment of the Polish diplomats in USSR in the fall of 1939 after Poland was divided between Germany and USSR. They were allowed to leave USSR (for England via Romania) unmolested, but as private citizens. I.e., the USSR made an effort to demonstrate that Poland is not a Nation anymore. Still, Romanians were allowed to take care of the Polish embassy building &c.
Related: What became of Nazi Germany's embassies in neutral countries?
Upvote:3
According to Diplomat in Berlin, 1933-1939: Papers and Memoirs of JΓ³zef Lipski, Ambassador of Poland., numerous Polish diplomats were imprisoned and/or killed by the Germans when they attacked Poland on Sept. 1, 1939. Polish Consuls imprisoned in Germany included
Consul Bohdan Jakowiecki who was imprisoned in Konigsberg and in concentration camps Hohenbruch and Dzialdow, where he died in Feb. 1941. Also, Consul Witold Winiarski, who was imprisoned in Konigsberg, died in concentration camp Dialdowo in August 1941. Consul Emil Schuller committed suicide in prison in Konigsberg in May 1941... 51 Polish foreign service employees were arrested by the Germans, 27 of whom were executed or died in concentration camps.
Upvote:4
German, Italian and Japanese diplomats (and others) were repatriated in exchange for Americans using Swedish ships to cross the Atlantic (Drottningholm and Gripsholm) that sailed alone with full lights and a distinctive paint coat. European axis diplomats were exchanged in neutral Portugal, where the Americans were brough by train. Exchanges took place at neutral ports; at Lourenço Marques in Mozambique or Mormugoa in Portuguese India with the Japanese, and Stockholm or Lisbon with the Germans.
Upvote:5
As for the case of the Japanese diplomats stranded in Washington: the wikipedia page about one of them says they were interned in Hot Springs, Virginia, and then, in July 1942, sent to a neutral country by a neutral ship. This web page seems to imply that they stayed at the luxurious Homestead resort in Hot Springs through May 1942 and then were transferred to the Greenbrier resort in White Sulphur Springs in West Virginia until being repatriated in July.