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Iran, reeling from the Trump administration’s “maximum pressure” campaign of economic sanctions, seems to have decided to apply maximum pressure of its own against the U.S. and its Western allies.

In the latest escalation, on Friday Iran seized a British oil tanker, the Stena Impero, in what the United Kingdom says were Omani waters.

Iran disputes the ship’s location when it was stormed by hooded Islamic Revolutionary Guard Corps forces, who swarmed the Stena Impero by small craft and helicopter before a British warship could intervene.

The claim that the tanker was in Iranian waters is likely a lie. The ship’s seizure was almost surely a response to Britain’s July 4 decision to detain an Iranian oil tanker near Gibraltar and headed toward Syria in violation of E.U. sanctions.

The U.K. rightly rejected the false equivalence. Iranian leaders “see this as a tit-for-tat situation, following Grace 1 being detained in Gibraltar. Nothing could be further from the truth,” British Foreign Secretary Jeremy Hunt told reporters on Saturday, a day after the tanker’s taking.

Hunt, who’s running against Boris Johnson to succeed outgoing Prime Minister Theresa May, may not last long in his job should Johnson, as expected, win this week’s intraparty contest.

There is no good time for a country to contend with a crisis like this, but it’s a particularly bad time for Britain, which is bogged down in Brexit and domestic politics, to try to defuse an international incident. The next prime minister may be tempted to turn to force, but that would endanger the 23 crew members and run the risk of a major military escalation.

Rather, the response should be internationalized, just as Tehran is trying to internationalize its response to the U.S. pulling out of the Joint Comprehensive Plan of Action (JCPOA), or Iran deal.

President Donald Trump made a mistake by unilaterally pulling out of the pact. Even his own administration agreed with international inspectors that Iran was in technical compliance with the deal. Trump was right, however, about Iran’s regionally destabilizing and malevolent actions. And the president made the correct call to hold off on a military strike in response to Iran downing a U.S. drone, which could have sparked a broader conflict.

“If the Iranians are convinced that the way to go is retaliation, we have a real problem,” Patrick Clawson, a senior fellow and director of research at the Washington Institute for Near East Policy, told an editorial writer. “At the moment they think they have what in strategic circles is called ‘escalation dominance’ — if the crisis escalates, they win.

“Breaking that escalation dominance is tough; we don’t want to get into a military tit-for-tat with them. That’s too dangerous … so what we need to try to do is to mobilize diplomacy and show the Iranians that they’re isolated. That’s not easy for this administration to do, and it would be very useful if the Brits and the E.U. took the lead on that.” (The Brits may be doing just that, augmenting the U.S.’s “Operation Sentinel” with their own European-led “maritime protection mission.”)

Multilateralism was the right approach to address Iran’s potential proliferation. In the same manner, a unified response would be the most effective method to respond to Tehran’s progressive provocations at sea.