Which attempts to create or revise states resulted in action?

I would love to see an answer to the "guiding questions" too.

Here I will provide a mathematician's (game theorist's, in this case) background on the subject, answering the question "qui prodest" - in case of one state splitting in two.

If you think this "side topic" has no place here, I will delete the answer.

Tax base: this is a zero-sum game: is those who secede are "rich", then they benefit from keeping their taxes to themselves, while those they secede from suffer. This is not interesting.

Presidential Elections: this is interesting because the Shapley value is super-additive! This means that the total power of the two new states will be smaller that that of the original state. This implies that the other states will benefit from the secession.

To make it clear, let us consider an example. Suppose we have a huge state which has over 50% of electoral votes. This means that this state determines the outcome of the presidential election completely. So its Shapley value is 1 and everyone else's 0.

Now that the state is split in half, the other states have a say in the presidential elections, which benefits them.

Congress: the share of representatives is proportional to the population and thus does not change, but the number of senators is fixed per state and this does change. Since this is more visible and simpler to understand than Shapley value, the other states might incorrectly think that the secession is against their interests because it dilutes their representation in the Senate.

Assuming we are talking about either failed petitions, or ones that have yet to bear fruit...

Wikipedia has a list of areas which attempted to become states, but failed.

As an Okie, my favorite example is the "colored" State of Sequoyah, which actually drafted a state constitution and petitioned to join the union in 1905. Congress however was not excited about the idea of a "majority-minority" state, nor the idea of Oklahoma and Indian territories becoming two small western states rather than one normal-sized one (somewhat diluting all the other states' power in the Senate). They insisted Indian Territory and Oklahoma Territory had to join as a unit.

There are always little state areas that feel politically neglected enough by the rest of their state that they threaten to form a new state. In general its not a very serious threat though. Article 4, Section 3 of The Constitution requires both state and Congressional approval for any such action.

New States may be admitted by the Congress into this Union; but no new States shall be formed or erected within the Jurisdiction of any other State; nor any State be formed by the Junction of two or more States, or parts of States, without the Consent of the Legislatures of the States concerned as well as of the Congress. ...

Congress has historically shown a preference for states of a rather uniform size and shape. Thus getting congressional approval for the splitting of existing states is extremely unlikely. Getting the majority of the existing state to agree seems like it would be problematic in most cases as well.

There is one major exception though. Texas by law has the option of splitting into up to 5 states if it wants to (without any further approval required from Congress).

Puerto Rico is a US territory that has had a serious ongoing debate about statehood since the 1960's. They have had multiple (non-binding) referendums on the subject, but the most recent one (2012) was the first to gain a majority support for statehood.

For information on more minor state border issues, I'd recommend How the States Got their Shapes. Its much more exciting reading than one might expect. (You'd think being part of the same country would prevent violent border disputes, wouldn't you?)

Vermont was split off from New York and/or New Hampshire. The Vermonters had provided the cannons needed to win the siege of Boston during the American Revolution.

Maine was split off from Massachusetts as part of the Compromise of 1820.

West Virginia was split off from Virginia during the Civil War.

So two themes are:

• It helps if your region is already organized as a discrete political unit (a la the Vermont District) or as a discrete region (Maine was not contiguous with the rest of Massachusetts) or is separated by military front-lines that do not seem to be about to move soon (a la West Virginia).

• It helps if Congress owes your region a debt of honor for either winning a war, preventing a war, or potentially winning a war.