With President Donald Trump reportedly contemplating radical measures to defend his beleaguered administration from investigation, the United States stands on the brink of a constitutional crisis. According to The New York Times, Trump’s staff is trying to dredge up opposition research to discredit special counsel Robert Mueller’s legal team on the investigation into the Trump campaign’s collusion with Russia in last election’s election interference. The Washington Post reports that Trump has inquired as to whether he can pardon associates, family members, and himself. And firing Mueller is a real possibility. As the New Republic’s Brian Beutler argued last night, there’s every indication that the Republican-controlled Congress will give a pass to these abuses of power, edging the American republic closer to authoritarianism.

Bob Bauer, former White House Counsel to President Barack Obama, wrote Thursday on the blog Lawfare that Trump’s gambit would end the investigation and leave only impeachment as a remedy, with Trump counting on Republicans in the House and the Senate to support him no matter what. This could pay off if the Republicans stay in line ahead of the 2018 midterm elections: at worst, if the Democrats took back the House, Trump would be impeached, but would remain in power since Democrats won’t have the two-thirds votes necessary in the Senate to remove him. Last night, Emma Loop of BuzzFeed interviewed four Republican senators about whether firing Mueller would be a mistake. Only one, Marco Rubio of Florida, unequivocally said yes.

All of this suggests that the constitutional crisis is also a political crisis. Democrats and the larger resistance needs to make Mueller the next big political battle. Defending the special counsel goes beyond defending one single investigation; it would be a proxy for a larger effort to guard the rule of law from a president with authoritarian aspirations. It would also be aimed at the Republican Party, letting them know that if they refuse to stand up to Trump’s thrashing of the rule of law, they will be held accountable at the election booth.

Politically, the time is right for such a pivot. The special congressional elections are in the rearview, all the key races lost, and the battle against Obamacare repeal appears to be ending with a Democratic victory. The party has the resources—the money for advertising, and energized activists for street protests—to pour into a major effort. It is time to make saving Mueller’s job the focus of a nationwide campaign.

One of the main reasons for mobilizing immediately is to elevate Mueller as a public figure—to make him a household name—so that firing him would become a more politically costly act. If Trump fires Mueller before the Democrats can make it a national issue, then the public will be playing catch-up with the story. The better known Mueller is, the more costly his firing would be to Trump.