(Bloomberg Opinion) -- If patriotism is the last refuge of a scoundrel, then foreign policy is the last refuge of a president facing impeachment. But Donald Trump will find it harder than Bill Clinton or Richard Nixon to use foreign policy to distract Americans from his own domestic political travails, whatever their ultimate outcome.

He didn’t help his cause with his plaintive tweet just before leaving for the NATO summit in London, reminding his 67.2 million followers that he would be at the summit “while the Democrats are holding the most ridiculous Impeachment hearings in history.” So much for changing the subject.

Say what you will about Nixon, but few modern-day presidents (George H.W. Bush may be an exception) had more experience with foreign policy or more inclination to conduct it. Even in the paranoid, self-pitying funk induced by Watergate, he mostly stayed on top of his foreign policy brief. When foreign affairs came up in meetings with Nixon, “it was just like giving him a needle,” recalled Admiral Thomas Moorer, then-chairman of the Joint Chiefs of Staff. “He would spark right up and get right in the middle of the conversation.”

Nixon was hardly above using foreign policy to distract the public from impeachment and try to burnish his leadership: As Walter Isaacson writes in his biography of Henry Kissinger, Nixon was “obsessed” with ending the Arab oil embargo, “a coup he thought might bring some relief from Watergate.” Even when the president gave vent to his worst impulses, he was restrained or deflected not just by his seasoned secretary of state, but also by a formidable Cold War-era policy-making machinery and bureaucracy. Although Watergate distracted Nixon from his presidential duties, historian Ken Hughes of the Miller Center told me via e-mail, “It never came close to crippling the functioning of the federal government.”

The same could be said about Clinton, who mostly succeeded in “compartmentalizing” the impeachment hearings and the Monica Lewinsky scandal from the running of government. As Nancy Soderberg, a foreign policy veteran of both his terms, later recalled: “My experience was that Clinton was more engaged in foreign policy than ever before…. Usually he’d read every memo you gave him, but not necessarily all the attachments. People were joking: now they’d come back with all the attachments with notes on them.”

“Compartmentalize” is not a word associated with Trump. Over the last week, impeachment has dominated his Twitter feed, the surest barometer of the presidential id. Nor can one imagine Trump — whose infrequent, keep-it-to-one-page intelligence briefings have sparked derision and concern — bearing down on decision memos as a form of escapism.

But the problem runs deeper than that: Even if he wanted to, Trump would be unable to immerse himself in the details of the national security process because there is no national security process. He’s on his fourth national security adviser in three years. His Secretary of State is increasingly focused on “workforce development” in Kansas (read: an open Senate seat) rather than running his department. Even before Trump’s defenestration and defamation of Marie Yovanovitch, the U.S. ambassador to Ukraine, Foggy Bottom was struggling with both internal scandal and White House scorn. (It’s also been saddled with a higher proportion of less qualified political appointments than under previous administrations.) As Colombia’s ambassador to the U.S. lamented last month: “The U.S. State Department, which used to be important, is destroyed. It doesn’t exist.”

Since the onset of his administration, Trump has made clear that he is “the only one that matters” on foreign policy. If anything, the impeachment hearings and his campaign for re-election (a pressure that neither Clinton nor Nixon faced) will only increase his tendency to improvise, either to blunt unfavorable testimony or to stoke his base. His announcement in Afghanistan last week that talks with the Taliban would resume, for instance, was as preemptory as his decision in September to cancel secret negotiations with them. Likewise his demand that South Korea increase its financial support for U.S. forces based there by 400 percent, more than the actual cost of their deployment and an amount that Pentagon officials struggled to justify to their Korean counterparts.

All this may be good campaign rally fodder, but it’s corrosive for the network of alliances that has underpinned U.S. security since the end of World War II. Look for similar political opportunism on a trade deal with China, negotiations with Trump’s “friend” Kim Jong Un, even Iran. With his political survival at stake, Trump is likely to try anything.

That prospective turmoil is no reason not to pursue impeachment. Congress has a constitutional duty to check executive overreach, and this president’s destructive impetuousness presents a unique threat to America’s global power and influence. Even if Congress ultimately fails to remove Trump from office, holding him to account will stand as a reminder to the world that the U.S. remains a nation of laws and democratic institutions.

To contact the author of this story: James Gibney at jgibney5@bloomberg.net

To contact the editor responsible for this story: Michael Newman at mnewman43@bloomberg.net

This column does not necessarily reflect the opinion of the editorial board or Bloomberg LP and its owners.

James Gibney writes editorials on international affairs for Bloomberg Opinion. Previously an editor at the Atlantic, the New York Times, Smithsonian, Foreign Policy and the New Republic, he was also in the U.S. Foreign Service from 1989 to 1997 in India, Japan and Washington.

©2019 Bloomberg L.P.