This is so depressing. Our country of civically unaware ignoramuses will truly be the death of everything our nation ever claimed to have stood for.
If I had to guess, democrats will probably be seeing some painful poll numbers in the coming weeks(as I mentioned). However the sheer scale of this crisis is still unknown and it's far too early to grade Trump's performance or the public's overall perception of it.
I guess the most apt comparison in my lifetime would be when Obama entered the White House in 2009. We were in a time of economic crisis, not unlike what we are dealing with now. Obama was the beneficiary of the "Rally around the Flag" effect. After his inauguration, he had a net approval rating of +40%. Yes, some of that was his honeymoon phase, but that net approval of +40% was more than double that of Bill Clinton and W. Bush when they first entered office. Anyway, his numbers gradually declined over 2009 for the very reason that he couldn't snap his fingers and fix the economic crisis(with some fearmongering on the right about The Affordable Care Act added in for good measure). Obama was barely above water in January of 2010.
While its not an apples to apples comparison(less time but Trump's bump is much smaller), I do believe that if this crisis lingers, the rally effect currently helping Trump will not last until the election. Even if Trump is not responsible for it, history tell us that the American people will start blaming him for the sole reason that he cant snap his fingers and fix everything.
I don't pertain to know whats going to happen, but I can hazard a guess that if this crisis lasts until November, Trump may very well be the underdog.