Before the long plume of black smoke from the stricken oil tanker Front Altair had cleared on Thursday, one thing was clear: the risks of a war in the region are real and rising fast. US officials briefed that it was “highly likely” Iran had attacked the Norwegian vessel and another tanker in the Gulf of Oman, close to the strait of Hormuz – a chokepoint for the global oil and gas trade. They had already blamed Tehran for mine attacks on other oil ships last month.

Iran’s foreign minister, Javad Zarif, was quick to tweet that “suspicious doesn’t begin to describe what likely transpired this morning”, pointing out that vessels with cargo for Japan were attacked as the Japanese prime minister, Shinzo Abe, met the supreme leader, Ayatollah Ali Khamenei, in a trip intended to help ease US-Iran tensions.

In reality, the question of who is actually responsible is subsumed by two more: who is held responsible, and who created the context for these attacks, which would have been unthinkable a year ago but now seem disturbing rather than surprising. Iran has plenty to answer for in the region, most of all perhaps in Syria. But it is the US that walked away from an international nuclear deal by which Iran was abiding, motivated largely it seems by Donald Trump’s allergy to any success by his predecessor. With ultra-hawk John Bolton at the helm, and egged on by the United Arab Emirates and Saudi Arabia, the US has pursued “maximum pressure”, strangling Iran’s economy and sending other threatening signals even as it says it would negotiate. The only real restraint on the president seems to be his promise to voters to save them from expensive Middle Eastern wars, and perhaps his desire to prove he is a better dealmaker than Barack Obama.

Yet as the jump in global oil prices following the attacks shows, Iran may not be the only one to suffer from the tensions. The US decision to disown the Iran nuclear deal and undermine its remnants strengthened hardliners in Iran and undermined moderates. Mr Zarif warned on Tuesday that the US “cannot expect to stay safe” after launching an economic war against Tehran. The supreme leader’s spate of tweets to Mr Abe sent a far more uncompromising message. Mr Trump is not a person deserving of an exchange of messages; the US could not stop Iran producing nuclear weapons; the US cannot be trusted.

China, focusing on its own troubles with the US, has not filled the economic gap as Tehran hoped. Iran is growing increasingly frustrated despite Europe’s efforts to shore up the nuclear deal. Though the UK, France and Germany have created the Instex mechanism to enable trading, it looks more like a political statement than an effective mechanism at present. Iran wants a serious injection of seed funding, which might persuade it to pause on its current path of escalation.

In the US, Congress has limited powers to constrain the administration, but can and should at least use its ability to increase and highlight the political costs of America’s current course. It has finally shown its willingness to take a stand over the war in Yemen.

It seems extremely unlikely that Tehran has any hubristic inclination to confront the US directly. Yet at present there is no sign that either side is willing to halt the escalation. Last month, after the first tanker attacks, the British foreign secretary, Jeremy Hunt, warned of the risk of a conflict happening “by accident”. An attack that causes mass fatalities, or any American death, could send this precarious situation over the edge. The blaze on Front Altair could yet turn out to presage a wider conflagration in the region, the devastating consequences of which could not be confined to Iran.