(CNN) - Marco Rubio's in Iowa Monday.
The first-term Republican senator from Florida's in the Hawkeye State to campaign for state senator Joni Ernst, the frontrunner in Tuesday's GOP Senate primary.
But anytime a potential White House contender visits Iowa - the state that kicks off the presidential caucus and primary calendar – the political world definitely takes notice. And Rubio's trip to Iowa comes a month after he traveled to New Hampshire, the state that holds the first primary in the race for the White House.
On the eve of the primary, Rubio joins Ernst at a early evening barbecue at her campaign HQ. And the two team up to talk to local reporters and join WHO's Simon Conway, a popular afternoon/early evening drive time talk radio host. And Rubio's Reclaim America PAC went up last week with a TV ad in support of Ernst, spending nearly $200,000 to run the spot statewide on cable TV, digital and radio.
"Excited to join @joniernst tomorrow at 5:00pm at her campaign HQ – final push!" Rubio tweeted Sunday.
Ernst, who's also a lieutenant colonel in the Iowa National Guard and who grabbed national attention earlier this year by touting her hog castrating skills in a campaign commercial, has the backing of some top names and groups among both the tea party movement and establishment Republicans.
Last week, the political wing of the Senate Conservatives Fund, which often backs conservative candidates that launch primary challenges against incumbent Republican senators, and the U.S. Chamber of Commerce, which mainly endorses mainstream Republicans, both went up with statewide ad buys in support of Ernst.
Friday 2012 GOP presidential nominee Mitt Romney campaigned with Ernst at two events in eastern Iowa. The state's lieutenant governor, Kim Reynolds, teamed up with Romney and Ernst at those events. And while not officially endorsing her, longtime Gov. Terry Branstad is a supporter. And she's also backed by the National Rife Association, which like the Chamber tends to support more traditional Republicans.
But she also enjoys the support of the political wing of Tea Party Express, a leading national tea party group, and former Alaska Gov. Sarah Palin, still influential with many on the right, also recently campaigned with her.
Ernst is facing off against three other major candidates in next Tuesday's primary – businessman Mark Jacobs, former U.S. Attorney Matthew Whitaker, and conservative radio talk show host Sam Clovis. If no candidate cracks 35% of the GOP primary vote, the nomination will be decided by around 2,000 delegates at a state party convention. A Des Moines Register poll released over the weekend put Ernst at 36%, 18-percentage points ahead of Jacobs, who was in second place.
The GOP nominee will face off in the midterm elections against Democratic Rep. Bruce Braley, who faces token opposition in his party's primary. The winner of November's general election will succeed longtime Democratic Sen. Tom Harkin, who is retiring at the end of the year. If Republicans flip Harkin's seat, and five other Democratic held seats, they will control the Senate.
Rubio and 2016
When it comes to the next race for the White House, it looks like Marco Rubio isn't laying low anymore.
Last month he was in New Hampshire, sounding like a presidential candidate, as headlined the Rockingham County, Republican Committee's annual "Freedom Founders" dinner, held at the historic Wentworth-By-The-Sea hotel just outside of Portsmouth. The senator slammed Democrats and in particular former Secretary of State Hillary Clinton, who's seriously considering a second White House bid, and if she runs would instantly become the overwhelming frontrunner for the Democratic nomination.
"Their ideas never worked in the 20th century, much less the 21st, and they're threatening to nominate someone now who wants to take us to the past, to an era that is gone and is never coming back," Rubio told the audience.
The dinner was just one stop during a busy day for Rubio in the Granite State. Earlier, he headlined a fundraiser for the state GOP, held private meetings with some influential Republicans, and sat down for interviews with local media.
Rubio quickly followed his New Hampshire swing with an appearance on ABC's "This Week," where said that he's ready to be commander in chief, "but I think that's true for multiple other people that would want to run."
Rubio added that should he decide to launch a 2016 presidential campaign, he won't run simultaneously for re-election for his seat in the U.S. Senate.
"It's a completely wide open GOP field. None of our fruit is ripe: To move from long shot to frontrunner, every potential GOP candidate has to grow, develop, or overcome a debility and Marco Rubio has as good a shot at doing that as anybody at this point," said Alex Castellanos, a veteran Republican strategist and CNN contributor who last year founded NewRepublican.org.
The recent moves by Rubio put the first-term senator back in the 2016 spotlight, which he's avoided for much of the past year.
Early last year Rubio's name was near or at the top of public opinion polls of Republicans' choice for their party's 2016 presidential nomination. But Rubio's numbers slipped after his high-profile support for a bipartisan comprehensive immigration reform bill that passed the Senate last June. The measure, which stalled in the House, included an eventual pathway to citizenship for most undocumented immigrants, which is strongly opposed by many conservatives.
Rubio's numbers in 2016 polls quickly faded, and have remained in the single digits in surveys asking Republicans their choice for the party's presidential nomination. Rubio stood in ninth place, at 6%, in the most recent CNN/ORC International poll, which was conducted a month ago.
Many of the other potential Republican White House hopefuls, such as Sen. Rand Paul of Kentucky, Sen. Ted Cruz of Texas, 2012 GOP presidential candidate and former Sen. Rick Santorum of Pennsylvania, Texas Gov. Rick Perry, and Louisiana Gov. Bobby Jindal, have made numerous trips to New Hampshire, Iowa and South Carolina, which holds the first southern primary, over the past year and a half.
Rubio did not, until now.