Why has Donald Trump transformed his foreign policy from isolationist to interventionist?
He doesn’t have some newfound curiosity in foreign affairs. Nor does he now deeply care about the global order. He’s shifted his focus for a different reason entirely: because his domestic agenda keeps getting stymied by checks and balances.
Unlike at home, Trump has few restraints on the global stage. He likes that environment much more.
He’s a bull who needs his China shop.
America’s domestic political system is resisting Trump more than many think. Sure, he’s gotten things done and caused lots of trouble. And to the victims of his abuses, the restraints on his power are far too weak.
But Trump’s domestic agenda has been muddled and underwhelming, especially for a president whose party controls Congress.
This is true even when the noise is screeching. Take DOGE, Trump’s partnership with Elon Musk. Remember how it was supposed to dramatically reduce federal spending?
For all its sound and fury, DOGE was largely negated by the very president who authorized it. About Trump's 2025 spending bill, Musk asked: “What’s the point of DOGE if the government’s just going to add $5 trillion more in debt?”
Moreover, while many Republicans slavishly acquiesce to Trump, not all of them do. Republican senators are rejecting his demand to end the filibuster. House Republicans are investigating the Epstein files.
The courts, for their part, rule against Trump regularly, including striking down his signature tariffs policy. His effort to undo birthright citizenship will likely soon meet the same fate.
State and local governments are likewise resisting Trump. Just look at California’s and Virginia’s broad gerrymanders in response to his (and his fellow Republicans’) election machinations.
The media–traditional and independent alike–have been fierce, notwithstanding Trump’s threats (and lawsuits). And the people in the streets, like in Minnesota, have made their voices heard.
Polling data suggests that Democrats will take the House in November. If they do, Trump will likely be impeached (again), and his legislative agenda will be in tatters.
Indeed, Trump has worthy opponents across American society thwarting his domestic ambitions.
Every single day.
But foreign policy, alas, is different. These checks don’t work internationally. A simple comparison illustrates the point: The same president who can’t get his political rival, Adam Schiff, indicted can unleash the might of America’s military on a whim.
Trump can largely do what he wants globally–including blowing up suspicious ships, taking out heads of state, invading sovereign nations, and threatening to end a civilization on social media.
It’s not supposed to work this way. The United States Constitution is ambiguous in numerous respects. But with declaring war, it’s clear: Article 1, Section 8 grants to Congress, not the president, “The power to declare war.”
“Only Congress can declare war,” Republican Senator Rand Paul said in March while protesting the Iran invasion. “That’s not my opinion. That's Article 1 of the Constitution … History will not be kind to a Congress that gave away its most solemn responsibility.”
As Trump's supporters emphasize, multiple presidents have initiated hostilities without congressional support. But numerous others have gone to Congress, as George W. Bush did in 2002 before the Iraq war.
One virtue of working with Congress before declaring war is that the public debate is more robust. Today, the American people are left to guess why Trump invaded Iran.
When he did so, without first seeking congressional authorization, he violated Article 1, Section 8 of the Constitution.
It’s that simple. Yet there was no practical way to stop him.
Congress moves far too slowly to block an aggressive commander-in-chief. And the courts can only do so much. Judges can force Trump to refund his tariffs, for example, but they can’t unwind the invasion of another country.
Ultimately, the person in the Oval Office is what matters most. As John Adams put it long ago, “We have no government armed with power capable of contending with human passions unbridled by morality … [which] would break the strongest cords of our Constitution as a whale goes through a net.”
Trump’s global ambitions flow from his domestic frustrations. The way to restrain him should be to follow the Constitution. That is, unfortunately, like trying to catch a whale with a fishing net.
Edward Larson is a Pulitzer Prize-winning legal historian, and William Cooper is an attorney and author. They cohost the podcast How Our Constitution Works And Why It Doesn't.
