I have no confidence in the DNC to not mess things up, and run a shitty candidate again. But Trump may have upset enough people that normally don't vote or usually cast a "protest vote" so we'll see. That's more than 2 years away though.
Unless Democrats can finally accept the fact that there is no grounds to impeach him and stop this almost 2 year long temper-tantrum they are currently experiencing he will win in 2020.
The special council investigation is headed by a lifelong Republican, who was appointed by Trump's own Deputy Attorney General, Rod Rosenstein, who is also a Republican, after the previous head of the investigation, also another Republican, James Comey, was fired. Not that Republicans are any more likely to be fair than Democrats. But the Russia investigation does not focus on Trump. There have been dozens of indictments, several charges and even guilty pleas. And that list keeps growing. It's not going anywhere.
And even if the investigation was focused on Trump, it took over 3 years to prove wrongdoing of Nixon. Had they stopped halfway through, he really wouldn't have been a crook, as he claimed. And at that point we didn't have an admission from his son that he agreed to meet a government official from a hostile nation for dirt on his political opponent. Etc.