Cameron’s Mar-a-Lago lobbying may not be enough to reach the new Republican party | David Cameron

Whatever happened at Mar-a-Lago between David Cameron and Donald Trump on Monday night, was clearly going to stay in Mar-a-Lago.

Dinner at the Trump Florida residence was always going to be a stiff test of the UK foreign secretary’s influence over the former president, presidential candidate, and the man he had previously referred to variously as protectionist, xenophobic, and misogynistic.

When Cameron was planning this week’s trip to Washington, the British embassy had advised him that if he wanted to help unlock US aid to Ukraine, his primary mission, it would be worth meeting the man who is orchestrating the persistent Republican block on that assistance.

The foreign secretary agreed it was worth a try, and the Trump camp was happy to oblige. Trump likes to present the Mar-a-Lago residence as the true presidency in temporary exile, and so encourages visits by foreign dignitaries.

A Trump spokesperson later listed the topics of conversation as including US and UK elections, Brexit-related policies, the need for Nato to meet their defence spending goals, “ending the killing in Ukraine”, as well as mutual admiration for the late Queen.

Despite being pressed repeatedly by journalists on Tuesday, Cameron would not even be that specific, insisting it was a private meeting, and that the two men had talked about “geopolitical” issues. British officials would say only that the meeting had been “warm and productive”.

What it did not produce is a meeting with Mike Johnson, the Republican House speaker who is holding back a vote on a supplemental spending bill that includes tens of billions of dollars critical for Ukraine’s defence against Vladimir Putin’s relentless onslaught.

British officials insisted that absence of a Johnson meeting was because their “two timetables could not be aligned”. But Cameron told reporters on Tuesday that he would make time to meet “any people in Congress who would welcome a conversation” about Ukraine aid. The misalignment clearly came just from one side.

The foreign secretary and former prime minister was due to spend Tuesday afternoon and much of Wednesday in Capitol Hill, a reflection of his enthusiasm for political cut and thrust, officials said, as well the advantages of having a lord for a foreign secretary. He does not have to rush back from trips abroad for constituency meetings or votes in the Commons like a member of parliament.

Cameron stressed on Tuesday he would bring every argumentative tool at his disposal to his talks with other Republican and Democratic leaders in Congress, from hard-headed national interest – it is a cheap way to degrade the Russian war machine and creates US jobs – to the thick seam of sentiment that runs through the history of the US-UK relationship.

“When I address this issue of how not to help Ukraine I can get very emotional about it,” the foreign secretary said, adding: “I think of my grandfather landing on the Normandy beaches under the cover of an American warship.”

Cameron also listed US-UK counter-terrorist actions that he had been involved in against the Islamic State.

“This is the same thing,” he added. “We face a huge threat from an aggressive Putin, taking another country’s territory by force. And it is so important that we stick together.”

Those sentiments will work with the Republicans Cameron was due to meet, including Mitch McConnell and Steve Scalise, the Senate minority leader and House majority leader, who are towards the Atlanticist end of the party.

Johnson might also have agreed with some of Cameron’s pitch, but that is besides the point. The threat to the speaker’s job is coming from that part of the Republican party that has no sentimental or ideological attachment to old alliances, no time for talk of “special” relationships, only loyalty to Trump.

The faction’s most vocal exponent, Marjorie Taylor Greene, has threatened to lead a revolt against Johnson and potentially topple him if he sends Ukrainian funding to the House floor for a vote. The Georgia congresswoman stepped up her attacks on the speaker on Tuesday morning, with a five-page screed to her Republican colleagues accusing him of failing to live up to any of his promises to his own party and serving “the Democrats’ agenda”.

Greene responded to an earlier Cameron lobbying effort on Ukraine’s behalf in February with an invitation to the foreign secretary to “kiss my ass”. There was no sign from the Mar-a-Lago dinner with Greene’s political godfather that provided any hope that particular invitation would be withdrawn.