US Sanctions Iran, Canada Tariffs, Debt Hits $40T

America’s most important policy instrument this week was the threat of exclusion. President Donald Trump promised an “economic D-Day” against Iran, Treasury Secretary Scott Bessent described the coming sanctions as the toughest in history, and Washington warned that countries sustaining Tehran could face severe consequences. The move followed months of war and a covert shipping corridor that US forces are using to escort roughly 15 to 20 tankers a night along Oman’s coast. Military power has kept some cargo moving. It has not restored ordinary navigation through the Strait of Hormuz.

The sanctions pivot is therefore both an escalation and an admission. Richard Goldberg of the Foundation for Defense of Democracies sees a strategy aimed at ending the Iranian regime rather than extracting a narrow concession. The Soufan Center is less confident about the mechanism: Iranian banks are already largely shut out of global finance and the country has survived nearly five decades of American pressure. The real test is China. Washington wants to punish buyers of Iranian oil without destroying a planned September meeting with Xi Jinping, while Tehran has warned that Gulf states joining the campaign would be treated as enemies. A weapon advertised as universal is likely to be applied selectively.

Canada received a less violent version of the same treatment. Talks collapsed after Ottawa rejected late US demands, and 50 percent tariffs took effect on roughly $20 billion to $28 billion of Canadian goods. Prime Minister Mark Carney promised dollar-for-dollar retaliation and said the old relationship would not return. US Trade Representative Jamieson Greer said Canada had introduced new demands after Washington offered relief on steel, autos and lumber. Nelson Wiseman of the University of Toronto called the dispute the largest test yet of whether a middle power can resist economic coercion. The answer will matter beyond Canada because the duties now reach goods that had been protected by the US-Mexico-Canada Agreement.

Pressure abroad coincided with diminishing financial room at home. Gross federal debt crossed $40 trillion on August 18, several months earlier than the Congressional Budget Office had expected, after growing by about $3 trillion in a year. Thirty-year Treasury yields traded above 5 percent and the administration signalled buybacks to steady the market. Bessent said there was “nothing magic” about the milestone, but his reliance on shorter-term bills leaves the government refinancing more often while inflation remains almost twice the Federal Reserve’s 2 percent target.

Kevin Warsh now has to explain that contradiction at Jackson Hole. His early communication as Federal Reserve chair has unsettled investors even as he insists on restoring price stability. Johns Hopkins economist Jonathan Wright argues that credibility will return through well-explained decisions, not repeated claims of superior resolve. That is also the larger lesson of the week. Sanctions, tariffs and bond-market intervention can buy time, but each asks counterparties and investors to believe Washington will carry the policy through without exempting a strategic partner or retreating from the domestic cost.

The next evidence will be practical: which Chinese and Gulf firms appear in the Iran package, whether escorted Hormuz traffic becomes routine, when Canada’s retaliation begins, and whether Warsh gives markets a clear reaction function. America still possesses unmatched leverage. Its problem is that every new use makes allies, adversaries and creditors calculate how much remains.