The US Constitution currently has no mechanism to break any individual State out of the Union. Throughout our history, this has been interpreted as a sign that the Union is perpetual, and not able to be dissolved. This got put to the test in our Civil War, where a bunch of states up and said "We're Leaving" and the Federal Government said "You can't just do that". They fought a war over it, and the Federal Government won, proving its position correct by force.

With that said, the US was founded as a government of the People, and so if the people want to carve out a way for States to leave, they must first establish a mechanism via amending the Constitution, which requires a 2/3 vote in both houses of Congress (or a Constitutional Convention) coupled with 3/4 of State Legislatures ratifying it.

There is a provision, though, to make States out of other States. Maine and West Virginia were both formed out of land that belonged to Massachusetts and Virginia.

CalExit was a russian disinfo plot to weaken the US, and Texit knows that, but they love russian disinfo.

Anything is possible with a constitutional amendment.

As a Texan who is working to create change in this state, please don’t kick us out. We aren’t only the bad things you see on the news. We can offer you:

Brisket
Big Tex
Cowboy Hats
Willie Nelson
Chuck Norris
Fried (insert any food group)
Everything cool about Austin
Czech kolaches
Boots galore
And so much more.

Help us. We are a lot more purple than the news makes it seem, and we have been gerrymandered to the point that we need more than a simple majority to create change. If you can find it in your hearts to assist us in becoming a swing state, the whole nation stands to inherit all the things that made Texas an iconic part of the country in the first place. We are worth the effort.

If it gets to that point, I think its more likely to declare the state in insurrection or rebellion and send in the army to passify it, rather than trying to expunge it.

Honestly Texas just needs to split into five states. Not everyone in the state holds the same beliefs as the people who live in north and east Texas. The Houston and Austin areas are far more progressive and liberal.

With enough approval, the US could do anything. It's either Constitutional or it would be Constitutional after an amendment is passed and approved.

If it is by the consent of the rest of the states, then yes. I'm not aware of any existing legal process, but a constitutional amendment could fix that.

Such a thing is unlikely to ever happen. Territory means people, infrastructure, and resources, so it's almost always better to hold onto it, unless you can't defend it.

It isn't. Until suddenly it is.

Most countries borders fluctuate during history.

I suppose it's possible but it would never happen unless that state basically committed an outright act of war against the rest of the US. At that point they probably would have left the US on their own though.

And even in that scenario the US government would probably send in the military to forcibly take that state back before they just give up and force them to leave.

Yeah. If Congress did it and the federal government just enforced it there's not much anyone could do about it.

A loud minority of Texans call for Independence, which is not really possible as far as I know

I'm a history illiterate so maybe I'm wrong but I'm sure lots of countries thought that before an insurrection. Not that I think Texas would rebel but literally why couldn't they?