Nobody is above the law, eh? How about under it? It turns out that the Democrats are worrying about the Insurrection Act of 1807. Signed into law by Jefferson, the act lets the president, “in all cases of insurrection, or obstruction to the laws” call up “the land or naval force of the United States, as shall be judged necessary.” This power was wielded by Jackson, Grant, JFK, and George H.W. Bush. The fear now is that President Trump, if re-elected, might use it.

Or mis-use it. The Act has proved flexible enough to cover efforts by President Grant to quell illegality by the Ku Klux Klan in the Reconstruction-era South and by Presidents Kennedy and Eisenhower to enforce school desegregation. It was used in 1992 to calm Los Angeles following the verdict in the Rodney King police misconduct case. So why the anxiety now that the law is a cudgel Mr. Trump could wield against violent protests on his watch?

“It’s a huge blank check, it is easily subject to abuse, it’s easy to imagine abuse,” frets a Harvard Law professor, Jack Goldsmith. The Wall Street Journal’s William Galston imagines Mr. Trump using the Act to stifle dissent, foreseeing a day when “more than 100,000 Americans have been arrested” and held “in barbed-wire encampments,” with no recourse because the president “has acted legally under the provisions of the Insurrection Act of 1807.” 

Mr. Galston’s fears appear to be based on a report in November in the Washington Post that the likely GOP nominee has “begun mapping out specific plans for using the federal government to punish critics and opponents should he win a second term.” Mr. Trump is weighing plans “to potentially invoke the Insurrection Act on his first day in office,” the Post reported, “to allow him to deploy the military” against protesters. 

Such fears appear overwrought. Critics worry that terms in the law like “insurrection,” “domestic violence,” and “rebellion” are, as Mr. Galston puts it, “undefined.” He argues “the risks of leaving such unfettered power in the president’s hands are obvious.” Yet in more than 200 years, the law has not once been abused in the way Mr. Trump’s critics fear. Mr. Trump even refrained from invoking it to quell riots in the summer of 2020, when it might have been useful.

The very breadth of the law’s authority reflects Congress’ intention, Justice Joseph Story noted in Martin v. Mott, the 1827 Supreme Court case that weighed an earlier version of the Act. The power to deploy the military in an emergency is of “a very high and delicate nature,” he wrote. It “results from the nature of the power itself,” he wrote, “to be exercised upon sudden emergencies” and in “circumstances which may be vital to the existence of the Union.”

In such situations, Justice Story wrote, there was no room for the give and take of legislative debate or such oversight contemplated by Democrats fearful of Mr. Trump’s notional post-reelection plans. “A prompt and unhesitating obedience to orders,” the justice wrote, “is indispensable to the complete attainment of the object.” The Founders, after all, knew rebellions could endanger the “domestic tranquility” that the Constitution was written to protect. 

Shays’ Rebellion in 1786 helped to spur the Framers to convene the next year to form a stronger central government. The Whiskey and Fries Rebellions — both tax revolts — required prompt action by Washington and Adams to defeat them. No wonder the Congress — and the high court — left it up to the president alone to decide if emergencies warrant calling up troops. Are anonymous rumors in the press a basis to strip that power from future presidents?

Justice Story conceded that “such a power may be abused.” He had more faith than others today in our law. The remedy, he said, “is to be found in the Constitution itself,” because “the watchfulness of the representatives of the nation carry with them all the checks which can be useful to guard against usurpation or wanton tyranny.” Even, he would no doubt add, any such misconduct as might be committed by the occupant of the White House in 2025.