Washington Gov. Jay Inslee made an important point during Wednesday’s CNN debate: If Democrats don’t take back the US Senate in 2020, they won’t be able to do anything.

“We are all going to work like the dickens to get more Democrats elected to the Senate. If we get a majority in the US Senate because of the position of these senators, not a damn thing is going to get done,” Inslee said. “And I’ll tell you why, with all their good intentions — and I know they’re sincere and passionate — but because they embraced the filibuster, Mitch McConnell is going to run the US Senate even if we take a majority.”

Inslee’s point underscored a stark reality for Democrats: Even if they beat President Donald Trump and take back the White House in 2020, they will still need to keep the House and retake the Senate to pass any policy. And even if they do take back the Senate by a bare majority — a stretch given the current Senate map — current Majority Leader Mitch McConnell and his Republican caucus would likely use the filibuster to try to obstruct a Democratic agenda.

In other words, either Democrats need to win back the White House and a supermajority in the Senate or eliminate the filibuster. Otherwise, McConnell will ensure their big ideas are toast.

Inslee advocated eliminating the filibuster in last month’s debate. It’s a controversial idea among some circles on Capitol Hill, but Inslee isn’t the only candidate talking about structural change. During CNN’s Tuesday night debate, South Bend, Indiana, Mayor Pete Buttigieg advocated for dramatic structural reform in American politics, including ending the Electoral College and passing a constitutional amendment to overturn Citizens United. Sen. Elizabeth Warren (D-MA) has also been a big advocate for eliminating the filibuster.

But Inslee’s argument is also prescient because multiple Democratic candidates running for president could be running for the Senate instead — most notably Democratic Gov. Steve Bullock of Montana, former Colorado Gov. John Hickenlooper, and former Rep. Beto O’Rourke of Texas (who unsuccessfully ran for US Senate in 2018).

There’s a staggering number of presidential candidates running, and a lot of people think some should pursue Senate bids instead.

Mitch McConnell is already calling himself the “grim reaper” of Democrats’ agenda. That’s not going to change

National Democrats are staring down a map that’s tough but not impossible, to retake the Senate. In order to retake a bare majority in the Senate, Democrats need to pick up four seats on net.

They’re on offense; a lot of Republican incumbents are up for reelection in 2020. But beyond easier potential pick-ups like Colorado and Arizona, Democrats’ path would have to weave through some combination of North Carolina, Maine (defeating Republican Sen. Susan Collins), and hang onto their Senate seat in deep-red Alabama.

But even if they manage to do all of that, the Senate filibuster stands in the way of any meaningful legislation.

The rules of the US Senate are set up in a way to give the minority party considerable power to obstruct the majority’s legislation, should they choose to use it. This is the power to filibuster bills by extending the debate on the bill, a tactic to block the bill from coming up for a vote.

McConnell is currently the majority leader of the Senate, but he’s already demonstrated you don’t need to be in the majority to have real power there. His repeated obstruction of Obama’s Cabinet and court picks led then-Senate Majority Leader Harry Reid to “go nuclear” and blow up the filibuster for the majority of nominees, making the required vote a simple majority rather than 60 votes.

“In the past, the filibuster has been used very sparingly,” Reid explained to me in May interview. “However, the Republican Congress in the last many years have filibustered everything so that 60 votes became the vote.”

Even when McConnell was in the minority, it became impossible to even confirm Obama’s judges or cabinet picks. If it was difficult enough to do that, it would be impossible to pass bold legislation that Democrats are debating now, like Medicare-for-all, or even a public option for health care.