I believe the Liberal Messiah would not let secession occur without a fight. The X factor in this scenario is the military. Would the U.S. Armed Forces (1) obey their Commander-In-Chief, (2) refuse to fire upon fellow Americans, or (3) splinter (for an example of this, read about the English Civil War).
Good questions. The Left won't and can't fight. Too wimpy. They'll try to use brave American soldiers to kill rebellious Americans.
During Watergate, there was concern that Nixon would order the Army to surround Congress and shut it down. The questions was whether the generals would obey the commander in chief or protect the country and constitution from a rouge president (per their oath). Nothing ever happened but the issue may again arise in some fashion. scary stuff. I'm not advocating revolution (I'll leave that to Ayers). Just thinking out loud.