By Niels Lesniewski, CQ Staff

As the Hispanic population of the United States grows rapidly, so too does the debate over its political effect.

(GETTY IMAGES/ AFP/ JEWEL SAMAD)

The latest talking point is research, released by a think tank that favors low immigration, that says there wasn’t much of an effect at all last November. The Center for Immigration Studies (CIS) says the immigration issue did not bring Hispanics out to vote in greater numbers, nor did it cause them to stay home. And it says Hispanics, along with the rest of the electorate, were more likely to vote Republican in 2010 than in 2008.

The Washington-based center cites exit polls from House races that showed an 8-point increase in the share of the Hispanic vote that went to Republicans, part of the wave that gave the GOP control of the House.

“If the failure to address immigration played a role in Hispanic voting, it seems to have helped Republicans,” CIS researchers Steven A. Camarota and Ashley Webster wrote in a memo last month.

However, Matt A. Barreto, an associate professor of political science at the University of Washington and director of the Washington Institute for the Study of Ethnicity and Race, says the entire premise of the CIS study is wrong. It runs counter to the results in individual races, he says.

“The most important takeaway from the 2010 election,” Barreto wrote, “was that it represented a very large increase in the Democratic vote share among Hispanics. This bucked the national trend in which more voters swung to the GOP. Among Hispanics, this was absolutely not the case, and in fact, it was a record-high vote for the Democrats.”

Barreto’s research group, Latino Decisions, says numbers in the exit poll don’t square with what happened in races such as the one for a Nevada Senate seat, where beleaguered Democrat Harry Reid , the Senate majority leader, defeated Republican Sharron Angle. Exit polls showed Reid got 68 percent of the Hispanic vote to 30 percent for Angle.

Barreto says Angle’s stated positions on immigration issues probably generated opposition among Hispanic voters. Reid, meanwhile, aggressively courted Hispanics and promised to hold a post-election Senate vote (as he eventually did) on the measure to provide legal status for some illegal immigrants who came to the United States as children. The bill was known as the DREAM Act.

Hispanic Voters A Limited Factor: Click here to view chart

Latino Decisions says polls of Latino voters are flawed. Notably, they chide the consortium conducting the exit poll for not having enough Spanish-speaking survey takers and for not having enough Spanish-language surveys — the implication being that a disproportionate share of Hispanics who show up in exit polls are those who are fluent in English.

Latino Decisions conducted a bilingual telephone poll on election eve that estimated that 90 percent of Nevada Latinos would vote for Reid, compared with the 68 percent reported by the exit poll.

The gap in results demonstrates the difficulty in accurately polling the population, something that had been identified as a problem after the 2004 election. The problem can only grow in significance as the voting-age population of Latinos increases.