Democrats' nightmare scenario

Some top Democrats are already predicting that President Trump will lose the popular vote again in 2020, but might very well win the election by a single electoral vote.

What they're saying: Jim Messina, President Obama's 2012 campaign manager, predicted the race will come down to two or three states, "We could be sitting on Election Day not knowing who will win."

Here’s one scenario, put forth by Cook Political Report's Dave Wasserman: 

• Democrats flip Michigan and Pennsylvania, increase their stronghold in California, and narrow the loss in Texas — helping Dems win the popular vote by nearly 5 million votes. 
• But Trump narrowly holds onto Arizona, Florida, North Carolina and Wisconsin — which Democrats are gunning for — and keeps the White House. 

"His electoral coalition is stronger in the states that matter (the Midwest, most notably) than it is nationally," said Kyle Kondik of Larry Sabato's Crystal Ball.

• Rep. Ted Lieu (D-Calif.) pushed back on the assertion that Dems are likely to lose Wisconsin again, arguing that's why the DNC is hosting the 2020 convention in Milwaukee.
• But don't forget Dems' 2016 national convention was in Philadelphia — and they lost Pennsylvania.
• And, according to a source familiar with Trump's re-election strategy, the campaign wants to collect as much Florida voter information as early as possible, so they can lock up that key state. That's why his kickoff rally was in Orlando.

The other side: "Everyone always speculates about the map and different states. At the DNC we take nothing for granted and our job is to build the infrastructure to ensure our eventual nominee has multiple pathways to 270 electoral votes," said David Bergstein, DNC Director of Battleground State Communications.

By the numbers: In 2016, Trump lost the popular vote by nearly 3 million votes. He won the electoral vote by 74.

Go deeper: Trump's 2020 map from hell