Trump tariff ruling shows top courts serve as last line of defence against strongman rule

The US Supreme Court told Donald Trump on February 20 that the tariffs he has used to try and bend the world to his will are unlawful. Tariffs are taxes and it is not for the president to impose them. According to the US constitution, Congress holds the power of the purse.

Trump relied on the terms of a 1977 law designed to address national emergencies, the International Emergency Economic Powers Act, to impose the majority of his tariffs. The court held that this law did not provide Trump with the legal authority to impose them.

In a post on social media following the court’s decision, Trump called the justices who ruled against him a “Disgrace to our Nation”. And he has subsequently announced that he will rely on another law, section 122 of the 1974 Trade Act, to impose worldwide tariffs of 15%.

But even if Trump’s use of that law survives legal challenge, these tariffs would be time limited. The act says that after 150 days the tariffs would continue only if Congress says so. Trump disagrees, saying in his State of the Union address on February 25 that “congressional action will not be necessary”.

Trump is a would-be “strongman” leader. Like all strongmen, his aim is to concentrate political power in himself and those closest to him. Since returning to the White House in January 2025, Trump has preferred to rule by way of executive order rather than through the legislative process. He has done so despite his Republican party controlling both houses of Congress.

Strongmen want to rule without the interference or oversight of legislatures and courts. But Trump has discovered that, in a constitutional democracy that is governed by the rule of law, the Supreme Court will not allow that to happen.

Resisting strongman rule

Trump is not the only western leader to experience push back from a top court when seeking to bypass the legislature. In 2019, Britain’s then-prime minister Boris Johnson wanted to fulfil his political promise to “get Brexit done” unfettered by parliament.

He advised the queen to suspend parliament for five weeks in the lead up to the UK’s “exit day” from the EU. The UK’s Supreme Court ruled unanimously that this advice was unlawful because, in the UK, parliament is sovereign. Parliament has two constitutional roles: to pass legislation and to hold the government to account.

The court held that Johnson and his ministers were constitutionally required to explain and justify their policies, decisions and actions to parliament and to answer parliament’s questions. Parliament must be free to exercise its constitutional functions, the court said, especially in times of great change.

The UK and the US have vastly different constitutions. But when faced with strongmen tactics, the supreme courts in both countries have stepped in to uphold the constitutional role of the legislature.

The function of legislatures in a democracy, US Supreme Court Justice Neil Gorsuch declared on February 21 after invalidating Trump’s tariffs, is “to tap the combined wisdom of the people’s elected representatives, not just that of one faction or man”.

In Israel, Prime Minister Benjamin Netanyahu (another would-be strongman leader) and his justice minister, Yariv Levin, have embarked on a programme of judicial reform in recent years to strengthen the power of the executive in relation to the judiciary.

The Israeli parliament passed amendments to the country’s quasi-constitutional Basic Laws in 2023, which aimed to limit the power of the courts to review ministerial decisions. These reforms have caused a constitutional crisis.

Protests were staged against the reforms across Israel in 2023, and military reservists threatened to not report for service. The protests ended abruptly with the October 7 terrorist attacks in southern Israel later that year.

Israel’s Supreme Court struck down one amendment to the Basic Laws in early 2024, with all 15 justices convening for the first time in Israeli history. The court held that it had the power to review the Basic Laws and declared an amendment – that would have limited the court’s ability to review ministerial decisions – unlawful.

However, the ruling has not derailed Netanyahu’s plans to reform the Israeli legal system. In 2025, the Israeli parliament passed a law that introduces more political control over judicial appointments. A case challenging this law will be heard by the full bench of the Israeli Supreme Court in summer 2026.

Meanwhile, Levin is refusing to cooperate with the president of the supreme court, Yitzhak Amit, to make judicial appointments. The Israeli government is also seeking to dismiss the independent attorney-general, Gali Baharav-Miara, who has argued against the reform.

In his response to the recent decision in the US to strike down Trump’s tariffs, French president Emmanuel Macron said: “It is not bad to have a supreme court and, therefore, the rule of law. It is good to have power and counterweights to power in democracies.”

At a time when strongman tactics appear to be on the rise, the courts are providing the last line of defence against authoritarian rule.

Andrea Loux Jarman does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.