@Nemo
Yes and no. On one hand, as you said, the North would be in big trouble if somebody planted explosions in the right urban centers, of which there are many fine choices to target, though that wouldn't be enough to kill their chances. It would be difficult to recover from such an attack. And also as you said, there are more guns floating around in the south, and I'll add that many aren't exactly legal for a pretty darn good reason. There is historical precedent to this-- the Union army had several more casualties than the Confederate army in the last Civil War and were much more likely to die in a Confederate prison than a Confederate would in a Union prison.
But on the flip side, the North borders on Canada, with which it has a very positive cultural exchange and economic relationship with. If the North gave Canada enough incentive, Canada could provide its own manpower and vast connections to aid the North. Compare that to the South, which borders on Mexico. A lot of people in the South tend to be hostile to the idea of Mexican help on top of Mexico lacking the same connections and manpower as Canada even if they do work something out-- and well, if Trump's gonna be in charge, he'll probably be too busy trying to build that damn wall and making himself look intimidating to ask Mexico for help. Again, you gotta remember that Trump lacks good strategy-making skills. He has been Leeroy Jenkinsing his way through life and shows no sign of stopping any time soon. Again, this will result in lots of Northern casualties as he recklessly (and sometimes in a confusing way) orders attacks on them. However, this also makes him prone to causing mass collateral damage, encourages mutinies and miscommunication, and will alienate him from the rest of the world who are bound to side with the North as a result. And well, if you thought the idea of promoting somebody to lieutenant or another critical leadership position just to help launch their political career as opposed to their military skills (very common in early America including the civil war) and picking people who valued glory over sense (very common during the Civil War) sounds like a disaster waiting to happen (and contributing factors to why the South lost), you'd make for a better general or chief strategist than Trump, his family, or his cronies. And even then, give the Confederates some credit, they at least don't choose to fire or hire core leadership on a whim or willingly choose to run a skeleton crew with several key positions vacant.
In short, the best General Trump and the Neo-Confederates can theoretically get for now is a pyrrhic victory. Even if they win, the damage they'd cause to American infrastructure, American lives and families, American economic influence, and American foreign relations would be so immense as to leave what remained in ruins with little room to recover while still maintaining their culture and beliefs. On some level, I think they know this, which is why all the begging for civil war tends to just be bravado these days. A Neo-Confederate doesn't want to start a war-- he wants somebody else to start a war for him and tell him what to do so there's other people to blame for whatever happens during and after the war that will take the heat off himself if its a disaster but also let him have the glory if it goes well for himself. Its scary and comforting at once-- on one hand no mass death and untold amounts of destruction any time soon which is good (obviously), but on the flip side, this has forced the work of a neo-con to be a hell of a lot more subtle than that of an old-school confederate while still really damaging and reprehensible and so much harder to stop and rally against.
Keep in mind that the North was badly disadvantaged at the start of the first civil war in America. Sure they had more people and had welcomed the Industrial Revolution with open arms, but said people were a good deal poorer and worse off as well as sorely lacking the economic, financial, cohesive, and political clout of the antebellum South. Its very easy to tell the how the South trounced the North in pretty much every early Civil War battle. The turning points were a series of strategic errors that gave the North enough ground to make a rapid recovery as well as the North's superior numbers. Sure the North had greater casualties but they also had a wider access to soldiers and let non-white soldiers in from the start, as opposed to the South which had less access to soldiers and didn't allow non-white soldiers until the very end of the war when it was too late for the measure to do any good for them. So casualties were less damaging to the Union effort than the Southern Effort. Its possible for the modern day North, which similarly boasts higher numbers and has an opponent seemingly bent on repeating the worst mistakes of the Civil War, to do something similar to win.
Also note that the Civil War was horrific in its own right. If the South had simply not kept pressuring and prodding the baby dragon that was the North with its growing embrace of the Industrial Revolution, it would probably still be as opulent as it was in the antebellum era. Unfortunately, that was not to be, and the South lost everything it was trying to maintain and grow. So please no more civil wars in America. Compromise is tedious, long, tense, and boring, but it is better for pretty much everybody involved long term.
