It really depends.
See, I was called absolutely crazy a little over a year ago when I outlined exactly what these groups were planning to do - including the whole bit about "separation."
The goal isn't exactly an independent nation. The goal is to establish something akin to the Palestinian Authority within the districts dominated by blacks. These 'Authorities' would have their own police force (the Black Panthers) that operates under its own set of laws that are largely independent. One could even look at them as something similar to the Cherokee Nation - except not a completely independent entity as they would still be the recipients of welfare beneficiary programs paid for by U.S. tax payers.
When you look at the movements in Ferguson and elsewhere, this was the objective. Police forces were given written demands by activist leaders that essentially served as fiat writs of law imposed via threat of mob violence. The goal was, basically, to expel State and Local authorities and seize control over the claimed region to become their own effective sovereign law.
... Which then promptly decided to burn down a few neighborhoods as a reminder that it could have been much worse if compliance wasn't met (which is, of course, false - a crackdown would have routed them pretty quick, but provided ample opportunity for 'police brutality' propaganda).
For the most part, they won't buy up large parts of land and try to move elsewhere to found a new nation. They will simply set fire to neighborhoods and begin racially motivated attacks upon civilians until people attempt to gift them the territory they want as a form of appeasement (because cracking down on that will always get spun as 'racism' - and everyone is afraid of being called a racist or flat-out blowing them all up in the middle of one of their rallies to put the fear of God/Allah/Aliens in them).
Look at the way the logic works - "this is our nation" and "everything here was built by slavery that we endured" - nothing about that pattern of thought suggests they will be keen on the idea of moving to the middle of nowhere and starting from scratch. They will lay claim to the homes, businesses, wealth, and people around them and argue that it should be theirs to decide what to do with.
That said, if they were to do such a thing - move out to the middle of nowhere and declare themselves independent - they would actually get a considerable amount of support from conservative groups should they come under attack from federal agents (look at the Bundy Ranch - there were a considerable number in the military, even who were in support of the armed civilians on the ground). There is a lot more animosity aimed toward the federal government, in general, these days for a variety of different reasons.
Granted - those are only unifying in the sense of people are tired of the way things currently are. Their ideas on what a more ideal system would look like are radically different and incompatible. Figures like King and Malcolm X were communist agents paid by the soviet union and served their cause well. Figures like Sanders will blend with that mentality quite nicely.
Conservatives divide between Nationalist and Constitutionalist lines. Nationalists tend to forget that the U.S. prior to 1930 was radically different than the U.S. that came out of the New Deal and the government-industrial complex of the Cold War. They want a return to a time when America was a world industry and technology leader with an economy that seemed to be reaching for the stars. They don't understand that the depression we feel today is precisely the result of the gimmicks used to create such a radical increase in apparent wealth.
Constitutionalists, for the most part, want to hit a massive reset button and throw out pretty much every federal construct since 1900 spare a few rights-based amendments - which would quite literally disembowel much of our current government as virtually every agency would be eliminated or restructured and reduced in its permissions.
There are several other views involved - but the net effect is that the U.S. is bound to split within our lifetimes. It will happen, and there will be wars, but a reunification will not occur through war as the ideology shift is simply too large. The South was willing to rejoin the North the first time because the difference was largely over government authority. The South set up a government that was very similar to what the U.S. Constitution established - they just believed the federal government should have less power and authority than it was exercising at the time - which was negatively impacting their economy and way of life. By the time they rejoined the union, much of their economy and way of life had already been permanently changed by the impacts of war - so it was really just an issue of swallowing one's pride.
The differences, now, are stark differences on what a government should be. You have socialists and borderline communists in one corner. You have nationalists with large centralized governments in another corner (with some bleed-through to socialism and Constitutionalism). Then you have Constitutionalists in another corner who want government bound and constrained to rigidly defined authorities (with some bleed-through to Nationalism).
You could also sub-divide the socialist group into Globalists and Nationalists. There are those who are still for the idea of a nation-state, and then there are those who are for the idea of completely eliminating nations in favor of globalized districts (Agenda 21 and all).
Toss in some of these groups like BLM/FYF/JOE - and while each and every one of them may have reason to unite against the federal government to some extent or another, not a one of them will agree upon what should replace it were it to be struck down.
The two who would come the closest are the Nationalists and the Constitutionalists - but even then, that is basically reviving the old debate between Federalists and Anti-Federalists back when the Constitution was first written - and that debate nearly sunk the fledgling U.S. at the time.
