Trump is already running for reelection in 2020. He lies more than ever since there are no consequences for it. His base either believes him or doesn’t care. The media still spread his lies even though they may correct them after the fact. Trump opponents complain but can’t do anything to stop him from lying. Trump lies so much it’s hard to tell if he’s lying or believes his false statements.
I assume he’ll still be president and still be a liar in 2020. This will have a major impact on the debates vs. the Democratic candidate. When (not if) Trump lies, who will do something? Who is responsible for correcting him? If the moderator does it, Trump and his supporters will say they are anti-Trump. If the Democratic candidate does it, it cuts into their time to tell the public about their plans. Just being anti-Trump is not a winning strategy.