The justices curtailed a tool that Donald Trump could have wielded against his political enemies.

On Friday, the Supreme Court upended the convictions of a group of January 6 defendants, ruling that the Justice Department had improperly prosecuted them under a statute that prohibits obstruction of an official proceeding. The justices found that the provision—which carries an extremely punitive sentence of up to 20 years in prison—applies to people who did things like alter or destroy documents or other evidence, not to people who disrupted a session of Congress by storming the Capitol.

As a result, a relatively small subset of people convicted for their role in the insurrection could be retried or resentenced and might spend less time in prison.

Many liberals were no doubt alarmed to learn that the conservative-dominated court had imposed new limits on January 6 prosecutions. That’s an understandable reaction, but it’s misguided. What the justices did was curtail the ability of the DOJ—an agency that may soon be under the control of Donald Trump—to put disruptive protesters behind bars for up to two decades.

The DOJ’s “novel interpretation” of the statute would “criminalize a broad
swath of prosaic conduct, exposing activists and lobbyists alike to decades in prison,” wrote Chief Justice John Roberts for a majority that included five of the court’s conservatives, as well as liberal Justice Ketanji Brown Jackson.

Roberts noted that during oral arguments, the Biden administration had acknowledged that its legal theory might allow the government to use the law against peaceful protesters who had purposefully disrupted an official proceeding.

In an amicus brief filed before the case was argued, a group of right-wing lawmakers made the rather ominous point that progressive protesters disrupt government events frequently. The Biden administration, they noted, hadn’t used the obstruction law to prosecute anti-Israel protesters who “occupied Capitol buildings to advocate for Congress to back a ceasefire in Gaza” or demonstrators who “interrupted Representative Jim Jordan’s House Judiciary
Committee field hearing” in a New York federal building. Nor, the lawmakers noted, had the Trump administration attempted to use this law against “the scores of protestors arrested for interfering” with Brett Kavanaugh’s Supreme Court confirmation hearings in the Senate.

Those protests were in no way comparable to the travesty of January 6. But that isn’t the issue. What that amicus brief makes clear is that if the DOJ’s interpretation of the obstruction law had been upheld, there would have been little stopping a future Trump administration from wielding its 20-year prison terms against political dissidents. Thankfully, the Supreme Court just made that a lot harder.