Sen. Marco Rubio made it almost official Monday.
The Florida Republican, who is expected to run for president, said he will have "something to announce" on April 13.
The first-term senator delivered his pre-announcement teaser during an evening segment on Fox's "The Five" and appeared hardly able to conceal what would be coming next month. His Senate term expires in 2016, and he cannot seek both elected offices at once.
"I will announce on April 13 what I'm going to do next -- in terms of running for president or the U.S. Senate," he said smiling. "I'll announce something."
Rubio has trailed in the polls. Firebrand Republican Sen. Ted Cruz of Texas last week became the first candidate to officially announce his campaign for president.
Another conservative favorite, Sen. Rand Paul (R-Ky.), the libertarian stalwart, is expected to announce his candidacy April 7.
Rubio has been quietly working behind the scenes to amass a campaign staff and draft a policy portfolio that many strategists believe will make him a stronger contender.
His upbeat message Monday was a prelude to the brand of conservative optimism he is expected to embrace, an approach aides believe will separate him from his peers.
"The country's really at a hinge point in terms of moving forward to the future," Rubio said. "We are really transitioning out of the 20th century and well into the 21st century, a dramatically different world.... It's really important that we move in the right direction as a country by not just confronting the challenges of this new era but embracing its opportunities."
The 43-year-old also intends to flex his foreign policy credentials, as he did on Monday, taking aim at the expected Democratic candidate, Hillary Rodham Clinton, and her turn as secretary of State.
"I don't think she has an agenda that looks forward to the 21st century," he said. "And she's the chief architect of a foreign policy that I think has been a disaster."
Rubio's biggest political hurdle, though, may be closer to home. The potential political heft behind fellow Florida Republican Jeb Bush, the former governor, poses an enormous challenge to the GOP field and threatens to splinter the big state the two call home.
The senator has also struggled to win back conservatives, who were disappointed that he played a leading role in the immigration overhaul that passed the Senate but ultimately fizzled in Congress.