The Hispanics with the highest profiles in this year’s political conventions, Sen. Marco Rubio of Florida and Mayor Julian Castro of San Antonio, stand as opposites in a cultural and political split that has divided millions of U.S. Latinos for decades.

Republicans chose Rubio, who is Cuban-American, to introduce Mitt Romney at the party’s convention last week. Democrats, meeting this week in Charlotte, N.C., picked Castro, who is Mexican-American, as keynote speaker, the role that launched a young Barack Obama to national political prominence.

Although they often are lumped together as Hispanics, Rubio and Castro are emblematic of acute political distinctions between Mexican-Americans, who are the largest Latino group in the U.S., and Cuban-Americans, who are the most politically active. Despite their shared language, these two constituencies have different histories in the United States and are subjected to distinctions in immigration policy that go easier on Cuban immigrants.

“Historically, many Cuban-Americans for the last few decades have tended to be a little more conservative. So it’s not surprising that you would see Sen. Rubio and the Republican nominee for Senate in Texas, Ted Cruz, running as Republicans,” Castro told The Associated Press. “And I don’t begrudge them for that. I think the policies they espouse are wrong, are not the best ones. But, you know, they’re doing what they believe. And I applaud them for that.”

Read more at NBC Latino