AUDIE CORNISH, HOST:

Public opinion polls indicate Latino Americans are far less enthusiastic about voting this Election Day than they were in 2012. Latinos still lean Democratic, but one survey found that a majority, 51 percent, disapprove of President Obama's handling of the issue they care about most, immigration policy. The president promised to take executive action to defer the deportation of certain undocumented workers but then pulled back.

Meanwhile, the polling from Latino Decisions believes other public opinion surveys often underestimate the Latino vote. Sylvia Manzano is a leading researcher there and explained why she thinks other pollsters get it wrong.

SYLVIA MANZANO: A lot of polling firms only do polling in English, and so that's going to exclude a pretty significant share of the Latino electorate no matter what state you're living in. So all of our interviewers are bilingual. The other thing that makes polling Latino voters difficult is the geographic concentration of the population. So when polls look for bellwether precincts, they're frequently looking at precincts that are diverse. And the fact is that most Latinos don't - or a large share don't live in diverse precincts.

CORNISH: They live in majority-minority districts.

MANZANO: They live in homogenous districts where people look like them, right? And so you're missing a very large share of the Latino electorate.

CORNISH: We've actually seen this in action, and some people point to the last race for Senate Majority Leader Harry Reid in Nevada. What happened there?

MANZANO: That's right. In 2010, Harry Reid was in a very tight contest, and he was running against a Republican candidate named Sharron Angle. She was running very harsh ads about immigration that had visuals of, you know, gang members and - let's just say they weren't very Hispanic friendly. And Sharron Angle was predicted to win by pretty much every pollster that was out there. But our polling showed that Harry Reid would win - in a squeaker, but that he would win. And what was different is that pollsters were not looking at the right proportion of the Latino electorate. They underestimated how many Latino voters were registered and how many would show up.

But it wasn't just a complete grassroots sort of rising to the polls. The campaigns invested very heavily there, so if candidates want to get the Latino vote, the onus is also on them. A lot of times people talk about, you know, Latinos don't turn out. Latinos don't turn out. But the question is what are the parties doing to get them there?

CORNISH: So in polling this year, talk a little bit more about what you're seeing in terms of party loyalty. Are Latino voters still leaning towards Democrats? Are they starting to change their minds?

MANZANO: Well, about a third of Latino voters tell us that the reason that they turn out to vote is to support the Latino community - not to vote for Republicans - not to vote for Democrats. So even though Latinos tend to break for Democrats and we expect that's probably going to happen today too, it's a pretty soft support.

Democrats have not invested very heavily in building a relationship with them. They've made some trade-offs on policy that have not sat well. They've soured the community in many ways. And the Republican Party - you know, it's no secret - has embraced a pretty antagonistic policy agenda and rhetoric that is really unappealing to lots of Hispanic voters.

CORNISH: In a midterm it's well-known that enthusiasm is down. Turnout is down. That's across the board. That's not just Latino voters in particular. But based on the numbers you're seeing, do you see a potential for turnout that would disprove those odds?

MANZANO: In some states, yes. Half of the entire Latino electorate lives in two states, Texas and California, and neither one of those are competitive. But if you look at places like Colorado where there is quite a bit of investment in Latino outreach and Florida where you have both parties actively spending money and have long-term relationships with the Latino community, you absolutely can expect to see Hispanic voters flexing their muscle there. You also might expect to see some things happening in states where Hispanics are a smaller proportion of the electorate, but it is such a close race that if they vote very cohesively, it could be a decisive factor - so in places like Kansas and Georgia.

CORNISH: Sylvia Manzano is a pollster with Latino Decisions. Sylvia, thanks so much.

MANZANO: Thank you very much. Transcript provided by NPR, Copyright NPR.