A Republican senator who lost re-election after Donald Trump endorsed his primary challenger said he got into a heated argument with the president on Wednesday amid discontent in Congress over the war with Iran and Trump’s demand that the GOP pass a bill that would impose a host of new rules on voting nationwide.

The squabble between Trump and the Louisiana senator Bill Cassidy erupted at a lunch in the US Capitol after the president abruptly cancelled a signing ceremony for a housing bill that passed both chambers with rare overwhelming bipartisan support on Wednesday. Trump said he would withhold his signature from the legislation, aimed at lowering the cost of housing, until Congress passes the Save America Act, which would impose new identification requirements on voters and curtail mail-in voting.

Cassidy, who placed third in Louisiana’s Senate primary last month after Trump urged voters to back a rival candidate, was one of four Republicans who the day prior had collaborated with Democrats to pass a war powers resolution that would curtail the president’s ability to resume hostilities against Iran.

Speaking to reporters following the tense luncheon, Cassidy said the argument began after Trump asked: “Why would anybody vote for the War Powers Act?”

“Is that a rhetorical question, or would you like to really know?” Cassidy said he replied.

When Trump demanded a response, the Republican senator said he stood up and told the president he wanted to know more about the conflict, noting his administration had said it would last four weeks but has instead stretched for four months without achieving US objectives. Cassidy said he reiterated that he would vote for war powers resolutions until he received a briefing that answered his questions.

Trump “did not particularly care for my comments [and] raised his voice”, Cassidy said, adding that the president pointed out his re-election defeat in an attempt to “demean” him.

“I lost my temper. That’s not appropriate, it’s the Irish in me,” Cassidy told reporters. “But I again matched his tone and his volume, and it went back and forth. But at some point my gut said, ‘OK, I’ll sit down,’ and so I sat down and tried to de-escalate.”

Cassidy said he believed he was doing his duty by pushing Trump for more transparency about the conflict.

“If the president and his team shares with the Senate and the House, and shares with the American people what is going on, then that satisfies my demand,” he said.

“But if you say everything’s fine, but on the outside it doesn’t look like everything’s fine, it is my responsibility to the people of the United States to ask for answers.”

Trump’s trip to the Capitol did not appear to resolve a legislative logjam over the Save America Act that has disrupted the Republican agenda ahead of November’s midterm elections, in which they will be defending their majorities in Congress.

In addition to linking passage of the Save America Act to his signing of the 21st Century Road to Housing Act, which passed with significant bipartisan majorities this week, Trump has also conditioned the renewal of the Foreign Intelligence Surveillance Act (Fisa), a key spy tool that expired earlier this month, on passage of the voting bill.

Democrats have refused to support reauthorizing Fisa in protest of the president’s appointment of an inexperienced loyalist, Bill Pulte, as acting director of national intelligence (DNI).

A path forward appeared to emerge when the president announced the nomination of the New York attorney Jay Clayton for the intelligence position on a permanent basis, only to derail his confirmation last week and allow Pulte to start his job as acting DNI. He also said any renewal of Fisa would have to be passed alongside the Save America Act.

Though the House of Representatives approved that bill in February largely along party lines, it has no path to passage in the Senate, where Democrats can use the filibuster’s 60-vote threshold to block its advancement.

Cassidy, who appears to have drawn Trump’s ire for voting to convict him after the January 6 insurrection, said that “the president just kind of talked and talked and talked and talked and talked” through their lunch, and the question of how to unjam the Republican agenda was left unresolved.

Trump offered little insight in brief comments following the meeting, describing it as “really great” while noting that “we like our leader”. That was an apparent reference to the Senate majority leader, John Thune, who has resisted Trump’s calls to tear up Senate norms, such as the filibuster, to get his agenda passed.

“We like everybody, really, in the room,” Trump said, though he nodded to the internal divisions, adding: “I don’t like a few people, but that’s OK.”

In a sign of frustration over the president’s interference, some Republican senators who emerged from the meeting replied sarcastically when asked to describe how it went.

“It was a great moment of fellowship,” said Thom Tillis, who is retiring from his seat representing North Carolina after clashing with Trump last year over his signature domestic policy bill. He described the mood among Senate Republicans as “one big happy family”.

Asked about the meeting, the Louisiana senator John Kennedy offered few details, but quipped: “Love is the answer.”

Trump’s trip to the Capitol was expected to see him sign the housing bill in a formal ceremony before meeting with Senate Republicans. The signing was abruptly cancelled even after chairs, a stage and a podium had already been set up.

Democrats seized on Trump’s spurning of the housing legislation as evidence that he was not serious about his campaign pledge to lower prices. The measure is intended to address climbing rents and home prices by reducing federal regulations, streamlining environmental reviews, speeding up the construction process and curbing the influence of corporate landlords by limiting their ability to purchase single-family homes.

Chuck Schumer, the Senate’s top Democrat, condemned Trump’s decision, saying: “It’s utterly amazing. Trump is running away from one of the very few accomplishments that could actually help the American people.”

Schumer predicted that if the president were to veto it, Congress would have the votes to override him. “The Save Act will not pass, Donald Trump. Get onboard with this housing bill,” he said.

Elizabeth Warren, who led the Democrats’ effort to negotiate the bill through the Senate, said in an interview that Trump’s refusal to sign the measure was proof that “the Republicans are in complete disarray. They’re shooting at each other.”

Referring to the president’s comments expressing “love” for inflation driven higher by the war with Iran and calling concerns about affordability a “hoax”, the senator said: “He’s told us the truth. It’s time for everyone in this country to believe him. He doesn’t care, and he is not fit to be president of these United States.”