"We have to come up with an immigration system that honors both our legacy as a nation of laws and also our legacy as a nation of immigrants," Rubio told The Associated Press on Tuesday.

An immigration plan from Rubio, the GOP's best-known Hispanic, could help Republicans make some headway with the fastest growing minority group and its 21 million eligible voters, many concentrated in the contested presidential battleground states of Florida, New Mexico, Arizona, Nevada and Colorado.

Democrats maintain a significant political advantage with Hispanics, numbers that were only strengthened by the harsh rhetoric from Republican presidential candidates in this year's primary. Hispanics overwhelmingly backed Barack Obama over Republican presidential nominee John McCain, 67-31 percent, in the 2008 presidential race and they favored Democratic congressional candidates 60-38 percent in 2010, according to exit polling. A Pew Research Center survey out Tuesday showed Obama with a solid edge over Romney among Hispanic registered voters, 67-27 percent.