On Tuesday in London, Mr. Trump and Theresa May, the outgoing British prime minister, said they had discussed Iran and remained committed to preventing it from developing a nuclear weapon. But they said they differed on the means because Britain has remained in the 2015 nuclear deal and wants Iran to do so, too.
Tensions between the United States and Iran soared in May after Mr. Bolton announced the administration was ordering the aircraft carrier strike group and bombers to the Middle East. American officials said new intelligence indicated a heightened threat from Iran or its allied militias that followed tighter oil sanctions imposed by the United States and the designation of an arm of the Iranian military as a terrorist group.
Though European allies and Democrats in Congress raised doubts about the threat level, Mr. Trump announced on May 24 that he would deploy an additional 1,500 troops to the Middle East. However, officials said he did so only reluctantly, and his vow to use military force has largely lacked weight, especially after comments in which he said he sometimes restrains Mr. Bolton.
Mr. Trump’s assertions that he is ready to negotiate sound hollow, too.
Questions about whether Mr. Pompeo was trying to secretly start a back channel to Iran dogged him on this three-night trip last week to Switzerland, a traditional interlocutor between Washington and Tehran. In the end, the speculation appeared overblown.
On Sunday, at a news conference in Bellinzano, Mr. Pompeo said he was ready to talk to Iranian officials with “no preconditions,” showing potential openness to recalibrating 12 demands he has made of Iran.
But standing beside Mr. Pompeo, Ignazio Cassis, the foreign minister of Switzerland, said neither the United States nor Iran had asked the Swiss to help with new negotiations.
“Both parties are now increasing the pressure, and for the rest, this is a matter of worry,” Mr. Cassis said, “but we cannot do anything unless we get a mandate from both parties.”