Florida Sen. Marco Rubio has stepped into two of the biggest domestic and foreign policy debates in the country over the last 24 hours.(Photo by Brendan Hoffman/Getty Images)

On Wednesday Rubio penned an op-ed in the Wall Street Journal coming out in opposition to raising the debt limit, a major bete noir of the tea party movement. (Congress must approve raising the amount of money that the country can borrow; traditionally it’s a no-brainer but tea party-aligned politicians believe authorizing further debt is a non-starter given the current state of economic affairs in the country.)

“We cannot afford to continue waiting,” Rubio wrote. “This may be our last chance to force Washington to tackle the central economic issue of our time.”

Then, late Wednesday came word — first reported by the Weekly Standard — that Rubio had penned a letter to Democratic and Republican leaders in the Senate pushing for the chamber to pass a use of force resolution against Libya that had as its stated goal the removal of dictator Moammar Gaddafi.

Within the space of 24 hours then, Rubio stepped in to the center of the hottest domestic and foreign policy debates in the country at the moment — and immediately drew national headlines for it.

“Marco’s original plan was to take some time and get a good feel for the Senate,” said Heath Thompson, an adviser to the Florida Senator. “The sheer magnitude of these issues, and Marco’s passion for what to do about them, has changed everything.”

Rubio came into the Senate already a star following his stunning ascent from a little known state legislator to the giant killer who drove Gov. Charlie Crist (I) out of the Republican party. Rubio rapidly became the face of the emergent tea party movement nationally and was touted as the next big thing on magazine covers and cable television chat shows.

Rather than play into that star status, Rubio seemed content to follow the blueprint laid out by Hillary Rodham Clinton following her election in 2000.

Clinton immediately became the most famous senator in the chamber upon her election but purposely played down that celebrity — declining most national media interviews while making a genuine effort to learn the rules of the chamber, make friends across the aisle and fit in.

Rubio spent the first three months of his Senate career doing the same, avoiding opportunities to build on the buzz around him. For example, Rubio didn’t address this year’s Conservative Political Action Conference — an early 2012 cattle call — after receiving a hero’s welcome at the gathering in 2010. (Rubio did record a video message to introduce former Florida Republican Party Chairman Al Cardenas at the event, however.)

Rubio’s office estimates that he receives roughly 200 meeting and speaking requests per week including invites to headline Lincoln Day dinners in places likes California and Ohio. He also turned down all national media requests before this week.

“Treating the Senate seriously and respectfully, rather than an immediate trampoline to the Oval Office, gives a senator the chance to more fully understand what works, and what doesn’t, in D.C., is appreciated by colleagues who can be in key positions to help you down the road, and gives you the institutional heft to develop a governing framework with practical applications before you try to take that nationwide,” said Eric Ueland, a former chief of staff to then Senate Majority Leader Bill Frist (Tenn.).

Rubio’s decision to step forward on two such high-profile issues as the debt ceiling and Libya — and take positions in opposition to President Obama -- will quickly ramp up talk (again) about his potential for national office.

The questions are already beginning. On Tuesday, Fox News Channel’s Sean Hannity asked Rubio about the possibility of being on the national ticket in 2012.

“I’m not going to be the vice presidential nominee,” the Florida Republican responded. “It’s important that I have that attitude too because otherwise I won’t be able to do this job well.”

Close observers of national politics — and the Fix is most definitely one -- know that’s a non-denial denial from Rubio about whether he would accept the vice presidential nod. And with Republicans needing to make up ground with Hispanic voters — and quick — Rubio will be at the top of almost any GOP presidential nominee’s list when the second-in-command search begins.

That reality — coupled with Rubio’ s rapid emergence as a vocal leader on two hot-button issues — mean the questions about his political future will keep coming fast and furious over the next months.