Once, when America was still very great, Presidents tended to be builders: they built things like the Interstate Highway System, which began, in 1956, under Dwight D. Eisenhower, a Republican, whose critics called it an “ascent into the stratosphere of New Deal jitterbug economics”; or they built protection from radioactive contamination, as when John F. Kennedy signed the Limited Nuclear Test Ban Treaty, in the fall of 1963, less than two months before he was murdered; or they sought to build domestic-policy systems, such as Lyndon B. Johnson did in order to give affordable health care to elderly and low-income Americans, which led, in 1965, to Medicare and Medicaid, legislation that probably would stand no chance of passing in today’s Washington.

But, if a wrecking ball could transform itself into a Presidency, it would look much like the one that’s been fashioned by the President we now have, Donald J. Trump. The interstate system is likely safe (and a boon to the fossil-fuel industry), except, perhaps, from potholes. The Clean Air Act, first signed into law in December, 1963, still stands, but the Environmental Protection Agency wants to undermine it by repealing the Clean Power Plan, which aimed to reduce the pollutants of the coal industry, and the agency, led by Scott Pruitt, no doubt has more ideas of that sort.

The Affordable Care Act has been under attack ever since it was passed, in 2010, but, rather than try to improve it, as Senators Lamar Alexander, a Tennessee Republican, and Patty Murray, a Washington Democrat, had hoped to do, Trump seems out to smash it, and, as Amy Davidson Sorkin recently wrote, he does not seem to care how that might affect those who need it most. Steve Bannon, Trump’s former strategist, has no doubt what his ex-boss intended in ending the federal subsidies. “Gonna blow that thing up,” Bannon said on Saturday. “Gonna blow those exchanges up, right?” In further signs of disrespect for the work of his predecessors, Trump has aimed a wrecking ball at the North American Free Trade Agreement, and, to the alarm of his own senior advisers, the nuclear deal with Iran. That’s bound to create more chaos, but Trump has shown himself to be adept at chaos.

When the nation recovers from this weird, disorienting, and vandalized era, thanks will go to people like Senator Bob Corker, the Tennessee Republican, whose loyalty to Trump had been sturdy, steady, and, at times, a little shameless—until, finally, it wasn’t. One definition of courage is a willingness to speak out while your peers remain silent, and Corker, among Republicans in Congress, is pretty much alone in expressing alarm at the shenanigans, tweets, and altogether unbalanced behavior of the President, although other Republicans, such as Senators James Lankford, of Oklahoma; Jeff Flake, of Arizona; and Ben Sasse, of Nebraska, seem uneasy, too. Nor was there any mistaking the target of Senator John McCain’s comments on Monday, in Philadelphia, when he said that “to abandon the ideals we have advanced around the globe . . . for the sake of some half-baked, spurious nationalism cooked up by people who would rather find scapegoats than solve problems is as unpatriotic as an attachment to any other tired dogma of the past that Americans consigned to the ash heap of history.” But Corker’s recent comments—most substantively in a conversation with Jonathan Martin, of the Times—were remarkable, and may have been driven by the motor of patriotic duty, by the idea that someone needs to say something; and if not now, when?

Corker is not seeking reëlection, which has afforded him a measure of liberation. But his bravery was nonetheless real, and his viewpoint disturbing: he apparently believes that the nation made a tragic mistake when it elected as President someone as unfit, as uninformed, as irrational, and as unready as Trump. Corker’s tweeted description of the White House as an “an adult day-care center,” trying to handle a tantrum-prone seventy-one-year-old, was, he said, a concern shared by nearly every Senate Republican—nearly every silent Senate Republican, he might have said. He stood in marked contrast to his party’s purported congressional leaders, Speaker of the House Paul D. Ryan and Senate Majority Leader Mitch McConnell, who seem fine with just about everything that Trump says and does, even when he shows contempt for them. (On Monday, Trump managed to say both that he could “understand fully how Steve Bannon feels” in declaring war on the Republican establishment, and, of McConnell, that “we’re probably now—I think at least as far as I’m concerned—closer than ever before.”)

“Look, except for a few people, the vast majority of our caucus understands what we’re dealing with here,” Corker said. He added, “Of course they understand the volatility that we’re dealing with and the tremendous amount of work that it takes by people around him to keep him in the middle of the road.” Corker was particularly concerned about the underminingof Secretary of State Rex Tillerson, who is among those trying to keep Trump from running off the road. On Friday, Corker told the Washington Post’s Jackson Diehl that Trump might have created a situation that could force the United States to choose between war and diplomacy in dealing with the nuclear threat posed by North Korea and Iran: “You cannot publicly castrate your own Secretary of State without giving yourself that binary choice.”

In late July, at the end of a Senate subcommittee hearing, a microphone close to Senator Susan Collins, a Maine Republican, caught her discussing Trump’s ignorance about the budget, and Senator Jack Reed, a Rhode Island Democrat, saying, “Yes. I think—I think he’s crazy,” a clear reference to the President. “I’m worried,” Collins said. So is the country: a recent Quinnipiac poll showed that fifty-six per cent of respondents believe that Trump is unfit to serve. That’s hardly a surprise; the nation, after all, is facing something that once was a premise to move the plot of Washington potboilers: What is to be done if a President is unstable, and wants to do something truly reckless? That question was at the heart of Corker’s conversation with the Times: “I know for a fact that every single day at the White House, it’s a situation of trying to contain him,” he said.

Seventy-some years ago, David Lilienthal, the first chairman of the Atomic Energy Commission, writing in his journal, asked a question that ought to have been asked when Trump, at the United Nations, threatened to “totally destroy” North Korea—raising the ultimate question about modern war: “Isn’t the real danger to civilization to be found in the recognition that warfare is no longer a conflict within limits imposed by morality, but without limit, without moral containment?” What, he might have added, if the wrecking ball is being aimed at civilization itself?