(CNN) - Sen. Marco Rubio made his final pitch Thursday for immigration reform, just hours before the Senate was set to vote on the comprehensive package that he helped create with seven other senators.
Taking refrains from previous speeches, the first-term Republican senator from Florida told the story of his own parents, who came from Cuba in 1956.
Rubio talked about his mother crying at the death of President John F. Kennedy and her feelings of joy the night man first walked on the moon. With each national heartbreak and heartache, he said, his parents became more assimilated into the United States.
"Well before they ever became citizens in their hearts, they had already become Americans," Rubio said on the Senate floor. "We focus so much on how immigrants can change America that we forget that America has always changed immigrants even more."
Elected with strong tea party support in 2010 and considered a potential presidential candidate, Rubio has faced scorn from those in the GOP who disagree with his immigration efforts.
The bipartisan group of senators known as the Gang of Eight announced in January they were drafting the immigration reform bill, which they formally unveiled in April. But Rubio has been pushing a need for changes in immigration long before that and has been known as a leading voice on the issue since he took office.
The plan being voted on Thursday includes a pathway to citizenship for most of the 11 million undocumented immigrants in the country illegally. Rubio backed a compromise amendment this week that added tougher border security provisions, but some conservatives in the House and Senate still question the legislation.
Rubio, who's acknowledged the anger he's faced by his own party, fiercely defended his push for immigration reform on Thursday in his closing remarks. Along with his own family's story, he talked about the nation's history of immigration.
"A collection of people from everywhere, we became one people, the most exceptional nation in all of human history," he said.
And his impassioned speech attempted to quell concerns that immigrants will have too much of an influence on the way of life in the U.S.
"Here in America, those who once had no hope will give their kids the chance at a life they always wanted for themselves. Here in America, generations of unfulfilled dreams will finally come to pass," he said "That's why I support this reform, not just because I believe in immigrants, but because I believe in America even more."
Following Rubio's remarks, Republican Sen. Jeff Sessions of Alabama said the bill was the wrong approach.
"I think the heart of America is good and they're willing to deal compassionately and not try to deport 11 million people and they want to do the right thing about this," he said, but added they want to do it by creating "a lawful system, a system we can be proud of, a system that serves the national interest."
Sessions argued the sponsors of the current bill "spent months in negotiations with special interests and lobbyists to produce a bill that will not work."
An opponent of the legislation, Sessions read aloud a statement from the unions representing Immigration and Customs Enforcement officers and the U.S. Citizenship and Immigration Services officers. The union presidents reiterated their opposition to the package.
"ICE officers and USCIS adjudication officers have pleaded with lawmakers not to adopt this bill," Sessions read from the statement. "The Schumer-Rubio-Corker-Hoeven proposal will make Americans less safe and it will ensure more illegal immigration, especially VISA overstays in the future."
"We urge all lawmakers to oppose the final cloture vote on Thursday and to oppose the bill, which we will be voting on soon," the statement continued.