Once again, the United States is undergoing the profound drama of presidential impeachment proceedings. But, unlike in the past, this time the implications for the rest of the world could be substantial.

Consider the two modern precursors to today’s impeachment inquiry into US President Donald Trump’s effort to persuade Ukraine’s government to announce a criminal investigation of one of his leading Democratic challengers, former vice president Joe Biden and Biden’s son. The first was the slow-brewing crisis that began with a midnight break-in at the Democratic National Committee’s offices in 1972 and went on to consume the US political system for two years, culminating in President Richard Nixon’s resignation in August 1974. The second was the special counsel investigation of President Bill Clinton, who was impeached in the US House of Representatives in 1998, but acquitted by the Senate in February 1999.

In both cases, the roots of the crises were domestic. Nixon was accused of misusing his office for domestic political ends, and then of obstructing the investigation. Clinton was accused of perjury and other abuses relating to his personal behaviour. The case against Trump is very different: US foreign policy is at its very center.

US relations with Ukraine are not some peripheral issue. America’s Ukraine policy is born of its commitments to European and international security. At least since Russia’s annexation of Crimea and incursions into eastern Ukraine in 2014, helping Ukraine secure its independence and sovereignty has been a central foreign-policy concern for both the US and the European Union.

Moreover, unlike the previous two impeachment crises, this one could jam up the machinery of US foreign policy. During Watergate, Henry Kissinger, serving simultaneously as secretary of state and national security adviser, kept the ship afloat, and both the Vietnam War and US–Soviet relations remained high on the agenda. Likewise, throughout the Clinton drama, which coincided with the run-up to the Kosovo War, US diplomacy and foreign policymaking didn’t suffer any major disruptions.

Obviously, the same cannot be said for the Trump impeachment inquiry. The proceedings have already revealed deep rifts between a foreign-policy apparatus that is trying to uphold the stated US policy on Ukraine and a White House that has been pursuing fundamentally different objectives. Whether that apparatus is still capable of carrying out its work on this critical issue is now an open question. On the White House side, there’s a noticeable absence of ‘adults in the room’. Under Secretary of State Mike Pompeo, who has been implicated in the scandal himself, an already diminished State Department has become a key battleground in the larger impeachment fight.

Moreover, Trump himself could make the current impeachment drama far worse for the rest of the world. During the Clinton impeachment proceeedings, the White House committed to maintaining business as usual and avoided participating in the daily partisan disputes of the process. Trump has already adopted exactly the opposite approach, not least by attacking (on Twitter) the former US ambassador to Ukraine while she was testifying before the House Intelligence Committee.

Clearly, Trump intends to obsess over every detail of the process. Every minute that he spends tweeting and watching Fox News will be time that other occupants of the Oval Office would have spent focusing on pressing issues of state. In this respect, the Trump drama has parallels to Watergate, which was clearly a distraction for Nixon. But given that Trump is even less constrained by (or even aware of) the constitutional principles that he is accused of violating, his efforts to derail the proceedings are likely to be even more brazen.

Whether Trump’s behaviour justifies removing him from office will be for the US Senate to decide. But whatever happens, America’s political crisis comes at a time of rising global instability. In addition to a revisionist Russia seeking opportunities for zero-sum gains wherever it can find them, an increasingly assertive China is flexing its muscles in Asia and on the world stage.

Meanwhile, the Middle East has entered another phase of profound instability, such that a single spark could easily ignite another crisis. North Korea’s nuclear-armed regime is contemplating new moves and conducting further ballistic-missile tests. Trade tensions remain high, despite the recent announcement of a ‘phase one’ deal between the US and China. And mass protests are sweeping the globe, from Santiago and Quito to Beirut and Hong Kong.

In today’s interconnected world, a crisis anywhere can end up on the desk of the US president, and the policy response that does (or doesn’t) come can have global implications. French President Emmanuel Macron recently made headlines by warning of an impending ‘brain death’ for NATO ^[1]. If that grim prognosis about the state of transatlantic relations was true earlier this month, it is all the more relevant now that the impeachment drama has reached a fever pitch.

In the previous impeachment episodes, the US remained a strategic actor on the world stage. But Trump’s America has already proved to be a source of global disruption. Whether the latest scandal leads to a strategic blow-up or merely a strategic timeout remains to be seen. The world can afford neither scenario.