Vice President J.D. Vance reassured Americans on Tuesday (May 19, 2026) that President Donald Trump's war with Iran will not become ‌a "forever war," using a White House briefing to defend his boss's policies as speculation about ​his potential successor builds.Standing in for press secretary Karoline Leavitt, who is on maternity leave, Mr. Vance fielded ⁠questions from journalists for nearly an hour in a mostly measured manner, a contrast to Mr. Trump's more confrontational style.He declined to rule out using taxpayer money to compensate people convicted of assaulting police officers during the January 6, 2021, attack on the U.S. ‌Capitol, dismissed European concerns over Washington scrapping troop deployment to Poland as overblown and called a reporter's suggestion that Mr. Trump's recent stock purchases raised corruption concerns "absurd."The White House briefing room has emerged this ‌month as an informal audition stage in the race to succeed President Donald Trump in 2028. Mr. Vance's appearance ‌at ⁠the podium came about two weeks after Secretary of State Marco Rubio, his possible future rival, drew ⁠wide attention for his debut briefing."Marco's right, this really is chaos," Mr. Vance quipped as reporters who packed the room shouted for his attention.When a reporter referred to Mr. Vance as "a potential future candidate," he rushed to correct her."I'm not a potential future candidate," he said. "I'm a ​Vice-President, and I really like my job, and ‌I'm going to try to do as good of a job as I can."Iran war presents political testMr. Vance, 41, a former Marine who has long argued against U.S. entanglements in foreign wars, on Tuesday (May 19) said any escalation with Tehran in the absence of a diplomatic solution would serve long-term U.S. security interests."This is not ‌a forever war," he said. "We're going to take care of business and come home."The Iran conflict ​is likely to loom over the political futures of both Mr. Rubio and Mr. Vance. Since it began on February 28, it has shut down a large chunk of the global oil trade, ⁠sending U.S. gas prices about 50% higher and raising alarm among Republicans defending congressional majorities in the November midterm elections.In a Reuters/Ipsos poll published on Tuesday (May 19), Mr. Trump's presidential approval rating fell to nearly its lowest level since he returned to the ‌White House, with many Republicans souring on his handling of Americans' cost-of-living concerns.The poll, conducted between May 15-18, showed some 34% of Americans have a favourable view of Mr. Vance and 33% said the same of Mr. Rubio. In January 2025, 42% of respondents in a Reuters/Ipsos poll said they had a favourable view of Mr. Vance.Even as both men downplay their 2028 ambitions, Mr. Trump has continued to fuel the succession talk. At a Rose Garden dinner last week, the President polled guests on his possible successors."Who likes J.D. Vance?” he asked. “Who likes Marco Rubio?”Both questions drew strong applause. ‌Mr. Trump said the men running together would make "a perfect ticket" but added he was not offering either of them his endorsement.Mr. Rubio's recent turn ​at the White House podium drew praise from Mr. Trump. Republicans and even some Democrats noted his smooth performance, which included quips with reporters and a 1990s hip-hop reference to describe Iran's negotiating ⁠position.A State Department video capturing his remarks that he hoped America would be a place where "anyone from anywhere can achieve anything" ⁠went viral and fueled further speculation of a 2028 bid.Mr. Vance, who has spent the last few weeks campaigning across states including Iowa, Maine and Missouri and raising money for Republican candidates, also tried out ‌some humour on Tuesday (May 19) in a reference to his wife, Usha Vance, who is pregnant with their fourth child."I told Karoline I would stand in for her today for the White House press briefing on the condition ​that when Usha has our baby in July, that she would be vice president for a couple weeks," Mr. Vance said