By Chris Adams, McClatchy Washington Bureau (TNS)

OXON HILL, Md. — Senator Marco Rubio of Florida delighted a gathering of conservative activists from around the country Friday morning, saying America doesn’t owe him anything but that he owes a “debt to America that I will never be able to repay.”

Before a mostly full ballroom at the annual Conservative Political Action Conference outside Washington, the Republican and potential presidential candidate recounted his personal history, one that took his parents — with little money, no connections and limited education — from Cuba to South Florida.

“Less than four decades later, all four of their children live the lives and the dreams that my parents once had for themselves,” Rubio told the gathering. “For me, America isn’t just a country. It’s the place that literally changed the history of my family.”

“The fact that the son of a bartender and a maid that worked in a hotel is sitting on the stage with you today,” he added later, “that’s why America is special.”

Rubio also worked to confront one of the most damaging — at least from the perspective of this audience — episodes in his young political career: the 2013 debate over immigration.

“Well, it wasn’t very popular. I don’t know if you know that from some of the folks here,” he quipped, to widespread chuckles.

The possible path to 2016 is tricky and tight for Rubio, once a darling of the nation’s conservatives but now viewed skeptically by many. Despite one of the most conservative voting records in the Senate, Rubio lost many of his conservative fans when he pushed a bipartisan overhaul of the nation’s immigration system that made it through the Senate in 2013 but stalled in the House of Representatives.

Rubio said he’d learned from 2013.

He acknowledged that there are millions of people who’ve lived in the U.S. for years and haven’t broken laws except for those on immigration.

“What I’ve learned is you can’t even have a conversation about that until people believe and know — not just believe, but it’s proven to them — that future illegal immigration will be controlled,” he said. “That is the single biggest lesson of the last two years”

In attendance were the heavyweights of today’s GOP, as well as the thought leaders, pundits and conservatives Rubio needs to reach and persuade in order to be a viable contender in 2016. Nearly all the potential presidential Republican contenders appeared at the event.

In his six-minute opening and a question and answer session with Sean Hannity of Fox News, the first-term senator from West Miami excited the crowd several times.

He pointed barbs at the Obama administration, and brought laughter with several lines — a couple joking about selling books he’s written.

In discussing his plans to revamp American higher education, Rubio talked about his own education debt: “I owed over $100,000 in student loans, which I paid off with the proceeds of my book —  now available on paperback, if you’re interested.”

Talking about his long-term political plans, he said, “I don’t want to be in politics my whole life. I want to serve our country and I’d like to do some other things. Like maybe own an NFL team or something. I don’t know. I’d have to sell a lot of books for that.”

Addressing both foreign policy and domestic themes, Rubio riffed on several “imagine” statements — conjuring what a new direction for the nation could bring.

Imagine if we repealed and replaced Obamacare, he said to applause.

“Imagine if we had leaders that understood that the family, not government, is the most important organization in society,” he said to more applause.

“Imagine if our laws protected innocent human life, from conception to natural death,” he said to even bigger applause.

Finally, to both applause and raucous laughter: “Imagine if we had a president who doesn’t travel the world bad-mouthing America. After all, that’s the U.N.’s job.”

Hannity proclaimed him a “great conservative, Tea Party senator,” and Rubio hit the themes the crowd loved. He also dinged, in one-word answers, the current occupant of the White House and one who’d likely be in Rubio’s way if he decides to run.

One-word answer on Barack Obama: “Failed.”

And Hillary Clinton: “Yesterday.”

Photo: Activists call for immigration reform outside of Senator Marco Rubio’s office December 10, 2014 (Rafael Gomez/Flickr)