Does Mike Pompeo realise what a foolish figure he cuts as he shambles around Europe, spouting risible tosh about Donald Trump’s commitment to a “new liberal order” and America as “force for good” in the Middle East? It seems he does not. Pompeo is a former soldier, Tea Party Republican, hawkish CIA chief and enthusiastic torture advocate who complained in 2013 that Guantanamo Bay inmates on hunger strike had “put on weight”. Self-awareness is not really his thing.

Whatever else he is, Pompeo is plainly no diplomat. Yet thanks to Trump, his job since April last year is US secretary of state, arguably the world’s most influential diplomatic post. It’s a role previously held by such towering figures as James Monroe, John Foster Dulles and George Shultz. By comparison, Pompeo is a political pufferfish floundering out of his depth. His latest self-inflicted embarrassment is Wednesday’s conference in Warsaw, envisaged (by him) as an international rally to put pressure on Iran.

The EU (including Britain) rightly regards Trump’s vendetta against Iran as dangerous and counter-productive

In the week Iran noisily celebrated the 40th anniversary of the Islamic revolution and its leaders dared the US to do its worst, Pompeo mounted a demonstration of his own. His cunning wheeze was to bring together the pliant nations of Europe and the Arab world in an American-led show of unity that would convince the terrified mullahs to forsake their “malign” activities. What this inept bumbling has achieved instead is to startlingly expose the deep and widening divisions between the US and its principal European allies.

Although the state department belatedly broadened the scope of the conference, the foreign ministers of France and Germany have boycotted Pompeo’s misconceived anti-Tehran hooley. So, too, has Federica Mogherini, the EU foreign policy chief who played a key role in securing the 2015 nuclear deal with Iran that Trump reneged on last year. The EU (and this, for the moment, includes Britain) rightly regards Trump’s vendetta against Iran as dangerous and counter-productive. Poor old Pompeo is seen as mere bagman, slavishly projecting his master’s voice.

Trump’s war of attrition against Tehran is accelerating rapidly. He misses no opportunity to denigrate Iran as the “world’s leading state sponsor of terrorism”, a phrase repeated to Republican applause in last week’s State of the Union address. The administration is threatening to follow up last year’s renewed, punitive US sanctions by cancelling oil import waivers for Iranian customers such as Italy and Greece. And it is pushing hard to undermine EU efforts to preserve Tehran’s adherence to the nuclear deal by maintaining non-dollar trade.

While Pompeo and Mike Pence, Trump’s vice-president, characterise the Warsaw conference as an attempt to create “a better, more stable Middle East”, it is ever clearer that Trump’s Iran obsession is distorting long-held policy goals and destabilising regional partners. The president’s rash decision to withdraw US troops from Syria – opposed by Nato allies, Congress and Pentagon generals – was motivated primarily by his desire to redeploy these forces to “keep watch” on Iran. To do so, he apparently plans to expand residual American bases in Iraq.

Facebook Twitter Pinterest US secretary of state Mike Pompeo with Polish foreign minister Jacek Czaputowicz in Warsaw this week. Photograph: Kacper Pempel/Reuters

Eight years after Barack Obama ended the Iraq war, Iraq’s Shia leadership and political parties, with close ties to Iran, are understandably alarmed at the prospect of the Americans returning – and using their country as a launchpad for a new conflict. Iraq’s Sunni minority – already the focus of efforts to regroup by displaced Isis terrorists – is not enamoured of the idea either. Having failed to consult Iraq in advance, Patrick Shanahan, Trump’s stand-in defence secretary, was in Baghdad this week trying to calm tempers.

European allies are meanwhile dismayed by both the signals Trump is sending and the company he keeps. Despite this week’s cornering of Isis in south-east Syria, they see a troop pullout as premature, and an invitation to the jihadis to bide their time and wait to fight another day. They see it as a strategic capitulation to Russia and tacit acceptance of Bashar al-Assad’s survival. And they see it as a betrayal of the west’s Kurdish allies and a green light for Turkey’s autocratic leader, Recep Tayyip Erdogan, to attack them.

Of even wider concern is the de facto alternative coalition that is coalescing around Trump’s banner, symbolised by Pompeo’s Polish waffle-fest. The unelected princes, panjandrums and potentates of Saudi Arabia and the Gulf – inveterate, unreasoning foes of Iran – are in Warsaw in force. They actively encourage the White House on its collision course with Tehran. Israel’s prime minister, Benjamin Netanyahu, is another keen conference attendee. He is presently authorising almost daily airstrikes against reported Iranian targets inside Syria, with Trump’s approval.

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Then there are the conference hosts. Poland’s rightwing rulers, at odds with Brussels over domestic policy, find a more congenial partner in Washington. Like Hungary’s Viktor Orbán, who Pompeo courted earlier this week, they share Trump’s aggressive nationalist-populist predilections. To their way of thinking, if the US wants to go after Iran, then so be it. It matters not, apparently, that Palestine, Yemen, Idlib, gross mis-governance and human rights abuses in Egypt, Saudi Arabia and Sudan, and a host of other problems are considerably more inimical to long-term Middle East stability than is beleaguered, battered Iran.

Pompeo’s Warsaw war rally marks another stage in the deliberate, Trumpian process of dividing and disrupting the postwar western alliance, to the point of disintegration. If it were not obvious already, this week’s bellicose tub-thumping demonstrates that Britain, France and Germany can no longer rely on rational, informed, balanced US leadership. And Iran cannot rely on the European powers to stop Trump’s next war of choice.

• Simon Tisdall is a foreign affairs commentator