Here's the most important lesson Dems say they've learned that will help them beat Trump in 2020

Democrats in the 2018 midterm elections have won almost 40 seats in the House of Representatives -- and the Democratic Party thinks it's found a formula that will help it defeat President Donald Trump in 2020.

Democratic strategists tell Bloomberg that the best way to defeat Trump is to ignore him whenever possible.

In particular, former Clinton campaign spokesman Brian Fallon tells Bloomberg that chasing after every outrageous thing that Trump said in 2016 backfired largely because it served to amplify his message.

"The lesson for 2020 is that when he does and says outrageous things, assume that it’s on purpose and remember that you don’t need to fight every battle that he chooses," he says. "We underestimated how much turnout he was able to generate in white rural areas by having extended fights on the issues he wanted."

Fallon admitted that the 2016 Clinton campaign believed that letting Trump dominate the conversation would highlight how unfit he was for the office of the presidency -- but this strategy also let him define the terms of the debate in ways that depressed potential Democratic voters.

"Trump’s greatest political strength is ability to move the political conversation off topics that matter to Democratic and swing voters and onto topics that excite his base," former Obama adviser Dan Pfeiffer tells Bloomberg.

Priorities USA Chairman Guy Cecil said, however, that Democrats couldn't entirely ignore Trump. Instead, he said they should only engage with Trump on their own terms on issues that will hurt him, such as his unpopular stances on tax cuts and health care.

Read the whole report here.