Is it a good idea or not?
To answer this question, we must take a huge step back and see what the lay of the land is from a purely objective point of view.
I'm a Texan, so that's admittedly hard to do. We're notorious for being quite proud of our state and bragging about it at every opportunity. Sometimes because it's true, but mostly because it irritates the lesser states.
For Texas to leave the union, the prospect would have to be less risky and more rewarding than staying. What would that actually look like?
Presently, Texas enjoys federal funding at multiple levels. This shifts what would be a large burden for Texans onto a much larger nation to share. Insofar as the federal government is explicitly enumerated such powers, this is fine. I personally feel we've gone way beyond that limitation, but that's a different discussion. If Texas left the union, that burden would return to the shoulders of Texans. This would likely come with a massive overhaul of what is and is not actually needed, and a painstaking discussion would have to be had to cut funding to things we simply can't afford on our own. In the long run, this would be a good thing in my estimation. Getting there would be quite painful.
So, sharing the financial burden with an entire nation is a benefit to staying. Leaving would be tremendously painful in this regard.
We also currently enjoy guaranteed protection from foreign invasion from the most powerful military on the planet.(it's debatable whether they're protecting from such at the moment, but again, a discussion for a different time) If we left, that blanket of protection goes away, and must then be negotiated, and we must rely on our own Guard to fill the gap until a proper army is established. Our Guard is considerable, but the transition phase would be a prime time for an invasion from multiple perspectives, and we'd likely be overwhelmed within a year while trying to ramp up defenses. This could be quelled with time, but it's a guarantee that some damage would be done, and likely some lives and land lost.
Being a part of the U.S., we're automatically included in all trade agreements that the country has with other nations. If Texas left, all of those would have to be individually negotiated, as well as a new trade agreement penned with the U.S. This could take a considerable amount of time to work through. Likely years.
Conversely, if Texas left the union, it would be able to establish its own federal constitution, establish a new set of judges, enforce laws as it sees fit without external influence, set up a new tax code, ignore the whims of various international bodies at will, and lay out its own course for the future. The magnitude of such a shift would be almost unthinkable, but such change is completely plausible. It could go really well, or horribly bad, depending on who plays a part and what an observer's perspective is on the matters being decided.
What would it take to force a secession?
I'm not really one to rely on pure democracy to settle such things, as the masses have been shown to be easily fooled and unreliable throughout history; especially recently so.
Some subjective markers would need to be established that would reveal how Texas is being unfairly burdened with bad laws, bad taxes, and bad protections.
Is the state bearing an unfair tax burden? Is the state suffering from a lack of enforced federal protection laws? Is the state being forced to adhere to federal laws it wholly considers unjust or unconstitutional?
Nailing these markers down would take a lot of debate between men smarter than me. Even more so taking on the task of hammering out the details of how we move forward after...
I'm still staggered by the simplicity and wisdom of our nation's founding documents, and the men that gathered to finalize them.
Do we still have such folks who can be trusted with that responsibility? The answer to that question might be my biggest reason for NOT wanting to secede. My confidence in humanity has wavered greatly in the last 20 years.
Things could be made so much worse in such a short time if the wrong people are given the wrong power.
At this time, I do NOT support secession. My knee-jerk reaction during the Obama administration was "hell yes, let's ditch this wreck".
Seeing what I've seen since then has made me more wise, and more pessimistic, with age.
And I'm not that old...