After all the debates and primaries and chatter from the political class, it all comes down to this: Tuesday's Florida primary may determine the next Republican candidate for president.
If Florida Senator Marco Rubio doesn't come in first - and collect 99 delegates in the winner-take-all contest, his quest is probably over.
"He has a chance, because the polls are narrowing. We never really believed the ones that showed a 20-point difference. He's closing, he's getting closer, he had a very good debate," University of South Florida political science professor Susan MacManus said after last Thursday's GOP debate in Miami.
She said this race reflects how important the Interstate 4 corridor is: Rubio spent much of the weekend in Central Florida, stopping in Largo, Hudson, Tampa and Lakeland, before greeting volunteers in Orlando and visiting The Villages.
"He's focusing on the I-4 corridor, no surprise there. Why? Because this is the muscle part of the state," she says. "He feels pretty confident about South Florida. But he needs good turnout for him here in the I-4 corridor and probably a little bit in the Jacksonville area."
For months, Floridians have been watching Rubio, Donald Trump, Ted Cruz and John Kasich slug it out on television. But the real difference between Rubio and the front-runner, Trump, can be seen at the reception they got at recent campaign stops in Tampa.
Trump's sold-out stop at the University of South Florida Sun Dome in February felt more like a rock concert than political rally. So many people showed up that Trump's speech was delayed 40 minutes so they could shoehorn people into the arena's rafters. People did The Wave while waiting, fanning signs in circles around the area that said, "The Silent Majority Stands With Trump."
"What an amazing event," Trump told the audience. "You know last night, we were in Baton Rouge, and we broke a record held for many years by Elton John - my friend Elton John. We had 12,000 and 4,000 or 5,000 outside, tonight I guess we have much more than that."
Much of Trump's appeal is that people are curious about the billionaire. One of those, USF college student Dominique Newcombe, said her attitude about him might have changed.
"He's not as scary in person," she said. "To be honest, I was terrified of him before I met him - I wasn't sure there was anybody that he liked. I'm just scared that he's got such a temper - that just really scares me to have that kind of temperament in a president, but I definitely like a lot of his ideas."
Last week, an equally enthusiastic- but much smaller crowd - less than one-tenth the size of Trump's event on the USF campus - showed up few miles away at the Tampa Convention Center to see Rubio.
Averill Massey of New Tampa came to see Rubio - even though she's a Canadian citizen and can't vote. She came because her husband and sons are American citizens.
"I believe that he's sincere in his conservative values, and his belief in America and what it can be again resonates with me," she said, "even though I'm not one."
There, Rubio brushed off a question about whether he would stay in the race if he loses to Trump Tuesday.
"We're going to win Florida," he said. "We're going to have to work hard - we're an underdog - I acknowledge that - but I feel good about the progress we're making every day."
His reason for being optimistic, he said, is he's the only Republican who has a chance of beating Trump in the Sunshine State.
"A vote for John Kasich or a vote for Ted Cruz in Florida is a vote for Donald Trump. I'm the only one who has any chance of beating Donald Trump in Florida. So if you don't want Donald Trump to be the Republican nominee, you have to vote for Marco Rubio."
MacManus said much of Rubio's political future hinges on how well he does in the primary, since he's giving up his Senate seat to run for president:
"If he comes within four or five points, that's OK," she said. "But if he loses by another 15 or 20, that's another matter altogether."
But she noted Rubio is only 44-years-old. So even if he goes down in flames on Tuesday, MacManus said he may get resurrected in another race, another day.