Washington (CNN)Sen. Marco Rubio seized his moment.
While two of his potential Republican presidential opponents were dodging press and scrambling to clean up gaffes on vaccinations, Rubio on Tuesday presided over his first hearing as chairman of the Senate Foreign Relations Western Hemisphere Subcommittee.
He peppered two panels of witnesses with pointed questions on President Barack Obama's move to normalize relations with Cuba, which he called "disgraceful."
And immediately after the hearing, Rubio became one of the GOP's fiercest advocates for vaccinations since the issue emerged as a political football this week, asserting children should "absolutely" be vaccinated.
It was a senatorial move from a senatorial perch for the Florida Republican, who has told his staff to prepare as though he'll run for president in 2016, though he hasn't yet made a decision publicly.
The hearing highlighted two of his primary advantages in the potential presidential race: His measured, charismatic speaking style, and compelling personal story and heritage.
But the hearing also hinted at the troubles ahead for Rubio, as he's vies for attention in a party crowded with rising stars and a different high profile issue seemingly each week. The U.S.-Cuba relations remain a less-than-glamorous storyline, and an initially packed hearing room cleared out midway through when most of the senators left to vote.
And with the threat from ISIS taking center stage in the debate over U.S. foreign policy, and others with considerable foreign policy chops, like South Carolina Sen. Lindsey Graham, contemplating a run, it remains to be seen whether the Cuba issue will be a sufficient launching pad to keep Rubio in the national spotlight.
Rubio opened the initially full hearing with a series of assertive and pointed questions for a State Department official, seeking to pin her down on whether the U.S. would agree to limit its meetings with democracy activists as a condition for the U.S. government opening an embassy in Havana.
"Can you categorically say we will never accept that condition?" he ultimately asked.
"It's not a real condition," the official replied.
While the questions were incisive, they came in stark contrast to Sen. Rand Paul's prickly interview with a CNBC host on Monday, during which he shushed her and yawned while she asked questions. The interview quickly went viral and drew him negative press.
And Rubio's appeal as the son of Cuban immigrants for a party seeking to make inroads with Latinos was on display during the second panel, which featured witnesses delivering testimony almost entirely in Spanish, with the help of a translator.
At one point, Rubio moved to ask a question after a witness had given her answer in Spanish, interrupting the interpreter. He apologized, adding, "I could understand."
"I told Sen. Flake...not to worry about the translation. I'll let you know what they said later" he joked, drawing laughter from the audience.
The senator's backers believe his experience on national security issues, and particularly his leadership on Cuba, could give him a leg up on the competition in the primary. Just last month, Rubio won high praise for his command of foreign policy issues at a Koch-sponsored panel that allowed him to differentiate himself from fellow 2016 contenders Sens. Rand Paul and Ted Cruz.
He emerged as the administration's most ardent critic after Obama announced in late December plans to thaw diplomatic relations with Cuba. And he's kept up the heat on the issue since, appearing on local and national media and writing op-eds hammering the move.
The subcommittee chairmanship, too, doesn't come without risks. If he ultimately decides to run for president, as is expected, he'll face questions about his ability to get things done on Capitol Hill.
Leadership of a subcommittee raises the expectations to deliver with concrete results — and can underscore the limits of a first-term senator's power.