Vice President JD Vance and Secretary of State Marco Rubio are both seen as possible contenders for the 2028 Republican nomination, especially with the two taking over White House press briefing duties one after another.On Tuesday, JD Vance took the press briefing room's podium, just two weeks after his possible presidential rival, Marco Rubio. (Reuters/AP)The press briefing room in the White House has almost become an informal audition stage for the intensifying race to succeed President Donald Trump in 2028.On Tuesday, Vance took the press briefing room's podium, just two weeks after his possible presidential rival, Marco Rubio.Vance worked to impress the briefing room full of journalists, fielding questions for nearly one hour as he filled in for White House press secretary Karoline Leavitt, who is on maternity leave.Vance joked about understanding the reporters' seating arrangement.He answered reporters' questions mostly in a measured manner, parallel to President Trump's more straightforward and confrontational style. Vance also seemed amused by the hectic events in the press briefing room and how reporters talked and shouted over each other for him to take their questionsHe quipped, "Marco's right, this really is chaos."In responding to reporters' questions, Vance defended Trump's decision on the Iran war and the newly-created $1.7 billion slush fund to compensate the US President's allies who believe they were politically persecuted, Reuters reported.A reporter even referred to Vance as a "potential future candidate" on Tuesday, to which he quickly responded, "I'm not a potential future candidate. 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."ALSO READ | Why Trump's disapproval ratings have hit an all-time high - Key factors in latest pollsNotably, Rubio's day at the White House podium even drew praise from Trump amid increasing speculations over the 2028 presidential race.Rubio also delivered answers to reporters in the press briefing room, with Republicans and some Democrats noting his 'smooth performance'. The State Secretary shared quips with journalists and also made a 1990s hip-hop reference to describe Iran's negotiating stance.Vance or Rubio? What does Trump think?While both JD Vance and Marco Rubio have downplayed their 2028 presidential ambitions, Trump has continued to fuel talks over who would succeed him.At a Rose Garden dinner last week, Trump polled his guests on his possible successors. "Who likes JD Vance? he asked. "Who likes Marco Rubio?"Both his questions drew massive applause, with almost equal strength, Reuters reported. Trump remarked that the two men running together would make a "perfect ticket", but indicated that it was still way too soon to make a call between them."That does not mean you have my endorsement under any circumstance," he added.On Wednesday, a day after Vance's turn at the White House podium, reporters asked Trump: "Do you think Vice President JD Vance or Secretary Marco Rubio did better in the press briefing?"Trump responded, “I think they both did great...I watched both of them. Both very good men -- really are.”