President Donald Trump has increasingly been asking advisers and friends a question that is fueling Republican speculation about 2028: “What do you think? JD or Marco?”

According to several people close to Trump, the president has repeatedly asked which of the two – Vice President JD Vance or Secretary of State Marco Rubio – they prefer as a future presidential nominee. Trump has also joked that the two should run together on the same ticket in 2028.

Trump advisers insist the president is simply entertaining himself and is not focused on the next election. Still, both men have taken on larger public roles ahead of the midterms, drawing growing attention inside the Republican Party.

This week, Rubio appeared in the White House briefing room answering questions about the Iran war before heading to Italy, where he met Pope Leo XIV and presented him with a crystal football. “Wow, OK,” Leo said to Rubio after receiving the gift. Rubio also met Italian Prime Minister Giorgia Meloni and is expected to accompany Trump on a trip to China.

At the same time, Vance traveled to Iowa to campaign for Rep. Zach Nunn, where he sharply criticized Democrats while reflecting on his own political evolution.

“It’s heartbreaking for a kid who came from a union Democrat family to realize that Democrats these days, they seem to care more about gender transition than they do about you keeping more of your hard-earned money,” Vance said.

The pair’s high-profile appearances have intensified speculation over whether Rubio could eventually challenge Vance for the Republican nomination. People close to both men say they are friends and do not want to appear to be rivals, though many acknowledge it is still far too early to know how the race will unfold.

“They both appreciate the moment, right?” Sen. Eric Schmitt said. “This is a historic comeback by a president who was out of office, who came back, and a unique coalition that, you know, brought that to be.”

He added: “I think that drives them to work together in addition to their kind of personal friendship.”

Rubio’s allies argue his broad appeal and visibility could help expand Trump’s coalition beyond the president’s core base. Republican pollster Whit Ayres said Rubio is capable of reaching Republicans who supported Trump without being deeply enthusiastic about him.

“He is a politician who could appeal to a whole lot of Republicans who went along with Trump but weren’t overly enthusiastic about him,” Ayres said.

Rubio himself has previously ruled out challenging Vance if the vice president runs.

“If JD Vance runs for president, he’s going to be our nominee, and I’ll be one of the first people to support him,” Rubio told Vanity Fair last year.

Even so, Vance is widely viewed as the current front-runner for the GOP nomination due to his close ties to Trump’s political base and growing influence inside the Republican National Committee.

“The logistical upper hand that JD has cannot be understated,” former Trump press secretary Sean Spicer said.

Still, political challenges remain for both men, particularly over the unpopular Iran war and concerns about the economy. During his Iowa visit, Vance acknowledged that two Iowans were killed in an Iranian drone strike on a military base in Kuwait earlier this year.

“We have to make this country worthy of that sacrifice,” Vance said.

Some Republicans also note that Trump himself could complicate any future presidential race, given his dominant role inside the party.

“The president understandably expects full loyalty from a vice president,” said Marc Short, former chief of staff to Mike Pence. “But in my experience he doesn’t really set up his vice president for political success afterwards.”