SEATTLE — Asian-Americans ought to be in the sights of politicians seeking swing voters.

More than half have no party affiliation, and in this presidential election 34 percent of those who are likely to vote still haven't made up their minds.

A new study, the National Asian American Survey (www.naasurvey.com/), digs more deeply into the political life of Asian-Americans than previous polls and gives insights that could help candidates reach out to the fast-growing groups, despite some of the challenges that would involve.

Asian-Americans tend to be lumped together in polls because of their relatively low numbers and discounted as a political force because they've been concentrated in a few states. But those factors have been changing rapidly.

This new study by four universities said there are now enough Asian-American voters to affect the outcome in several swing states, including Florida and Michigan.

Seventy-five percent of Asian-Americans live in just 10 states, mostly in the West, but from 1990 to 2000 the Asian-American population more than doubled in 19 states.

Overall, the study found 41 percent of Asian Americans are likely to vote for Barack Obama, 24 percent support John McCain and 34 percent are undecided.

This study surveyed large-enough numbers of voters to unearth differences among the various Asian-American groups that should make it easier for campaigns to sharpen their vote-getting strategies:

Vietnamese-Americans backed McCain over Obama 51 to 24 percent.

Among Japanese-Americans, 60 percent supported Obama, as did 53 percent of Asian Indian-Americans.

Chinese-Americans backed Obama 41 percent to 12 percent for McCain, but 43 percent were undecided.

Filipino, Korean and other Asian-Americans were closely divided, slightly favoring Obama, but many were undecided.

I asked University of Washington political-science professor Matt Barreto about the differences. He's director of the UW's Institute for the Study of Ethnicity, Race and Sexuality and one of three UW professors who gave advice to the survey's researchers.

Voting is affected by country of origin, generations in the U.S., religion, and the experiences that typically shape a person's world view.

Vietnamese-Americans have some similarity to Cuban Americans politically, Barreto said, in that people who immigrated during and after the Vietnam War embraced Republicans, whom they viewed as tougher on the communist regime in their former homeland.

Religious beliefs may also be a factor. Catholic Filipinos and Korean Americans who attend evangelical churches may hold socially conservative views that affect their political preference.

All of that still needs to be explored in more depth, Barreto said, but the study is a big step beyond previous polls.

It said 37 percent of Asian-American registered voters report being contacted by a party or campaign organization. In a study after the 2004 election, 43 percent of all voters reported contact.

Barreto said follow-up studies will help explain remaining questions, such as the extent and effectiveness of those efforts to reach voters.

New immigrants, including many Latinos and Asian Americans, tend to get less information about politics, Barreto said. "Both candidates are running commercials on Spanish-language media but not Asian-American media."

Language and other barriers do make getting information to, and from, some newer populations difficult. That's one reason this new survey was not only multiethnic, but was multilingual, too.

Trying to reach everyone might be too difficult, but with better data, candidates can pick which group to focus on in a given state.

And as the number of Asian Americans continues to grow, it will become increasingly important for national candidates to make the effort.