As great as that all sounds, it seems that people don't really care much about Trump being corrupt. They just think it is part of his charisma. He's the bad boy that always brings someone home. I can actually see the war thing being a pro for Trump. Being a "War President" gets you reelected though it didn't work for Johnson or Truman. Bush II solidified himself with Iraq, even if it seemed that a slim majority of Americans were against it by November 2004.
With those caveats, there is a high chance that Trump does something that finally is straw the breaks the camel's back though I imagine that comes after there is a new Congress there that is willing to investigate it. The economy running out of steam or that right now a bubble is forming and will soon burst will be enough to give Democrats back Congress or at least the House. It will probably take more than that to finish off Trump. The double-dip wasn't enough to stop Reagan and a weak economy was able to slow down but not beat Clinton, Bush II, or Obama.
All in all, it is my guess is that Trump won't do himself in and that Democrats still have their work cut out for them.
It really depends on how bad the scandal would be. We haven't had a massive media circus scandal since Monica, and if we want to go back further, Iran-Contra or Watergate. If something happens on that level, which with Trump I don't see being an impossibility, that'd be very bad for his reelection prospects (obviously).
On the economy, it's also important to remember that Reagan/Clinton/Obama pretty much their first elections because the economy was sh**. Trump otoh won in a situation where the economy is ok, and if it gets any worse over the next four years, the blame's going to placed on him and the GOP.
