What would Russia do if there was a similar military group trying to annex part of eastern Russian territories to Japan?
What would the United States do if there was a Mexican-American militia trying to annex Texas or California to Mexico?
It would be foolish or naive to assume their would be okey with it and do nothing about it.
The individual States of the USA are individual nations. Constitutionally the US Government only has authority regarding State borders and certain aspects of State banking.
Thirteen counties in Oregon are petitioning both, the government of Oregon, and the Federal government to drop their Oregon Statehood and become part of Idaho. And there are at least 3 more that are seriously thinking about it.
Benefits to Oregon are that they would have a whole lot more money to play with, because these counties are draining certain State government funds. The benefits to the people of those counties are that the people think way more like the people of Idaho than they think like Western Oregon people. When the voice of the people becomes stronger, the change will happen.
In other words, government is about two things:
1. Serving their people;
2. Serving themselves.
Ukraine wanted to be free from Russia in the 1991 shutdown of the Soviet Union. Did they want to be free just so they could make slaves of their people? Or are they going to offer the same freedom of choice to their people that they received in 1991?
Government is the rule of the few over the many. Ukraine is doing to many of its people just the same thing that the Soviet Union was doing to Ukraine. The difference this time is that the US is behind what Ukraine is doing to its people... slavery, not freedom.