President Trump’s retreat on tariffs calls to mind Churchill’s jibe in 1956 after Britain’s Suez debacle: “I would never have dared; and if I had dared, I would certainly never have dared stop.” That foreign policy fiasco signaled the end of British pretensions to be a global power. While Mr. Trump’s reversal on tariffs isn’t a calamity on a par with Suez, the episode does raise concerns that the national debt served to hamstring the president’s plans on a key policy. 

Today’s announcement of a pause in the “Liberation Day” regime of reciprocal tariffs came barely a day after the new levies went into effect. The démarche had sent stocks swooning and, more importantly, put pressure on bond yields — especially long-term debt. A benchmark for borrowing costs, the yield on 30-year Treasury bonds, briefly rose above 5 percent, Bloomberg reports. That raised fears that the Fed would find it necessary to intervene.

A central bank rescue, though, could have exacerbated the worries over America’s outsized debt. That’s the insight from economist Thomas Simons, who contended, before Mr. Trump’s volte-face, that “mass purchases of Treasuries” by the Fed “might raise questions about the monetization of debt in the US, and further weaken the market’s appeal among foreign investors.” Did the turmoil in the debt market force Mr. Trump’s hand on tariffs?

If so, that, too, is, in a sense, an echo of the Suez crisis, when Britain was forced to abruptly terminate its campaign to recapture the critical canal in part due to pressure from the global financial markets. America’s hostility to the British military operation led to “speculative pressure” on the pound, historian James Boughton writes. Britain had to deplete its dollar reserves, and its move to withdraw its troops came as a devaluation of the pound loomed.

Mr. Trump is attributing his policy reversal in part to the “queasy” reaction of the debt market. That “spooked economists,” as the BBC put it, because of American debt’s traditional role as a “safe haven” in times of turmoil. The rising yields on debt suggested an “erosion” of this status, said Allianz’s Mohammed El Erian. It serves as a reminder of the power of bond markets to move politics — and also of the danger posed by America’s surging national debt. 

That’s a caution these columns marked when the Congressional Budget Office head, Phillip Swagel, warned that America’s “unprecedented” national debt ran the risk of a, in the Financial Times’ telling, “Liz Truss-style market shock.” That was a meltdown that struck the Britons when the ex-premier proposed a supply-side, pro-growth tax cut. The International Monetary Fund and debt markets, in effect, claimed Britain couldn’t afford it. 

Mr. Swagel’s words, we said, were “a reminder of the perils of profligacy,” underscoring how the bloated national indebtedness could yet infringe on America’s freedom of action. “The danger,” Mr. Swagel said, “is what the UK faced with former prime minister Truss, where policymakers tried to take an action, and then there’s a market reaction to that action.” That warning came more than a year ago, though, and since then our federal debt has kept soaring.

“Imagine the outrage,” we explained, “if, at some point, plans to reduce federal income taxes, or embark on a military buildup, were nixed by such holders of American debt as, say, Red China, Japan, Saudi Arabia, or the European Union.” That scenario was foretold by Mr. Swagel if America failed to act on its “ballooning federal debt.” Did Mr. Trump’s tariff plans — designed to even the global playing field on trade — run afoul of lenders to America?

The White House is putting a brave face on the tariff pause, with Secretary Bessent suggesting it was the “strategy all along.” Today’s hasty reversal casts doubt on that claim. Amid the wrangling in Congress over the budget, the role of the debt market in the tariff tumult underscores the urgency for Mr. Trump and Hill Republicans to put America’s fiscal — and monetary — house in order. The nation’s independence could be at stake.