While it is clearly too early to judge the long-term ramifications of the president’s decision to order the killing (my colleague Uri Friedman has set out the dangers of accidental escalation), the initial assessment among many in the foreign-policy establishment here in London is not quite what you might expect. The attack—in the view of analysts and British officials I spoke with (the latter of whom requested anonymity to discuss government discussions)—has, at a stroke, reasserted American military dominance and revealed the constraints of Iranian power.

Although Trump’s foreign-policy strategy (if one even accepts that there is such a thing) has many limits, his unpredictability and, most critically, his willingness to escalate a crisis using the United States’ military and economic strength has turned the tables on Iran in a way few thought possible. What is more, the strike has exposed the gaping irrelevance of Europe’s leading powers—Britain, France, and Germany—in this whole crisis. The “E3,” which have long sought to keep the Iranian nuclear deal alive by undermining the U.S. policy of “maximum pressure” on Iran, have so far failed to do so. This week, they were finally forced to admit the apparently terminal collapse of the Obama-era nuclear deal, releasing a joint statement to announce that they were triggering its “dispute resolution” clause because of Tehran’s failure to abide by the terms of the agreement. The reality of the situation is startling: Europe’s attempts to keep the deal alive have achieved little in Tehran because of the Continent’s powerlessness. And European opposition to Trump’s Iran policy has achieved even less in Washington. In an interview, Boris Johnson all but admitted defeat in keeping the nuclear deal alive, calling instead for a new “Trump deal.”

To some extent, one British diplomat told me, the air strike that killed Soleimani was an extreme snapback to the hyperrealist, Kissingerian principles that largely guided American foreign policy after the Second World War. In this view, Barack Obama and his cautious multilateralism were the break with the norm, not Trump.