Will Chief Justice Roberts strike down Trump’s tariffs, or remain his lapdog?

Chief Justice John Roberts is at a crossroads. Will he rule against President Trump in the tariffs case or be Trump’s loyal lackey? Trump insists that his self-imposed tariffs are lawful and that a court order invalidating them will be a disaster. Others, including lower federal court judges, 12 states’ governments, and some small businesses, insist that Trump’s tariffs are outright illegal because they are without statutory authorization.

At the recent Supreme Court oral argument, it looked as if enough justices are leaning strongly against Trump that his imperial presidency is about to experience a major loss.

Roberts is nothing if not a loyal conservative Republican whose judicial black robe camouflages his decades-old strong political tilt to the right. Although he has deviated now and then — his fifth vote in the Supreme Court decision upholding the Affordable Care Act is perhaps the most publicly acknowledged instance — he has over the years as the nation’s 17th chief justice loyally advanced a Republican set of values.

Roberts wrote the decision invalidating a key provision of the 1965 Voting Rights Act that had been essential to protecting the voting power of Black Americans in some states. In dissent, he asserted that the Supreme Court decision upholding same-sex marriage had nothing to do with constitutional law.

Roberts opposes a broad right to an abortion. He handed Republicans a gift too grand to be assessed when he ruled that political gerrymandering did not present a legal question that was capable of judicial resolution. During the summer of 2025, Roberts and his conservative colleagues so frequently upheld Trump’s emergency appeals that one might fairly wonder whether the Supreme Court ceased to be a co-equal branch of government.

Roberts must now demonstrate to the nation that he understands that his primary responsibility is to uphold a constitution that strengthens American democracy as opposed to advancing a Trump administration conservative political agenda. If he does, he will join a long list of respected justices who understood that, within the American governing scheme, they had unique responsibilities in protecting separation of powers principles and policing presidential assertions for enhanced political power.

In 1952, the court lowered the boom on President Truman when, during the Korean War, it ruled that he lacked statutory authority to seize the nation’s steel mills to avoid a strike which he claimed he needed to do to keep the steel mills operating since they supplied the armaments required on the Korean battlefields.

In 1974, five years after President Nixon appointed him to be chief justice, Warren Burger wrote the opinion in the Nixon Tapes case that effectively ended the Nixon presidency.

In 1937, Chief Justice Charles Evans Hughes delivered a decisive blow to President Franklin Roosevelt’s court-packing plan when he wrote a letter to the Senate demolishing FDR’s public rationale for adding more justices to the court. During that same period in the 1930s, Louis Brandeis, a loyal supporter of Roosevelt and his New Deal legislation, chewed out FDR’s top political operatives after the court invalidated FDR’s National Recovery Industrial Act and told them to tell the president that he was going too far in insisting upon new presidential power. 

Chief Justice Earl Warren, a Republican, annoyed Republican President Dwight D. Eisenhower when in 1954 he led the court to rule unanimously that mandatory race segregation in the nation’s public schools was inherently unequal.

The nation needs an independent Supreme Court. During the first decades of the 19th century, Chief Justice John Marshall established the court as a third co-equal branch of government. Hughes reaffirmed that political principle during the tumultuous decade of the 1930s. Warren made judicial independence a national calling card when southern senators, outraged over the formal end to Jim Crow, launched an “Impeach Earl Warren” campaign. To the surprise of many, Warren Burger upheld the independence of the court in the Nixon Tapes case.

The nation needs a court to support outcomes that strengthen the nation’s democracy and the rule of law. To no one’s surprise, that requires upholding separation of powers principles which puts a premium on a very simple fact: Congress makes the nation’s laws, not the president.

The tariffs case just argued before the Supreme Court brings this sharp distinction to center stage. In 1977, Congress passed the International Emergency Economic Powers Act. It aimed to clarify and curtail presidential power during a national emergency. In doing so the statute does not use the word tariff and thus does not explicitly grant the president power to impose tariffs. For Roberts that was significant. As he noted during the oral argument, since Congress has used the term “tariffs” in other provisions, its absence in the very text of this law strongly suggest that it does not grant the president authority to impose tariffs.

The nation needs Roberts to see beyond Republican Party values, and beyond the Trump administration’s incessant claims for more power. We need Roberts to shine some light on the American political experiment so that it flourishes instead of wilts.

David Rudenstine is an American legal scholar and the Sheldon H. Solow Professor of Law at Cardozo School of Law, where he served as the Dean from 2001 to 2009. Professor Rudenstine has previously written about the Supreme Court, with a new book expected on former Supreme Court Chief Justice Charles Evans Hughes.