Former Florida Gov. Jeb Bush once described Asian-Americans as the "canary in the coal mine" of the Republican Party, saying that if Republicans didn't make more of an effort to court the fastest-growing racial group in the United States, the party would pay a price at the polls.

Now a new report from the National Asian American Survey finds not only that Asian-Americans continue a steady drift away from the GOP, but that the party may be losing one of its most reliable ethnic groups.

Among registered Asian-American voters, the survey found Democrat Hillary Clinton had a 4-to-1 lead over Republican Donald Trump.

Alton Wang, a communications associate with the nonpartisan group APIAVote, said many Asian-Americans are increasingly turned off by anti-immigrant and anti-Muslim rhetoric. More than 1 in 5 respondents were undecided. This is especially key because swing states, including Nevada, Virginia and North Carolina, have sizable Asian-American populations with undecided voters.

One group stood out. Vietnamese-Americans were once considered a reliable Republican voting bloc. But since 2008, more voters identified as something other than Republican. Here's what the survey found:

"In the past, Vietnamese Americans were the only Asian American group more likely to identify as Republican than Democrat. In 2008, 42% of Vietnamese American registered voters identified as Republican, compared to 23% in 2016. Among this group, non-partisan identifiers are growing. In 2008, 40% of Vietnamese registered voters identified as independent or claimed they did 'not think in terms of political parties,' but this number rose to 47% in 2016."

Vietnamese-Americans, many of whom came to the U.S. as refugees after the Vietnam War, stood out in one other way: They were among the least likely to say they support accepting Syrian refugees into the United States.

Trump has made opposition to Syrian resettlement in the U.S. a key part of his campaign.

"It's so ironic and contradictory to their history as refugees," said Linda Vo, a professor at the University of California, Irvine who has been trying to make sense of this inconsistency. "I've asked these individuals, 'Why would you be supportive of a candidate [Trump] who is anti-refugee, anti-immigrant, when you yourself came as one?' "

Janelle Wong, one of the NAAS researchers, who also heads the Asian-American studies department at the University of Maryland, broke the data down for me even further. She said Vietnamese-American respondents who are younger, U.S.-born and with a college degree were more likely to say they'd welcome Syrian refugees. Of all the groups surveyed, Vietnamese-Americans were the most divided: 34 percent said they opposed accepting refugees; 27 percent refused to answer the question or said they didn't know; and 38 percent said they favored accepting refugees. This is in stark contrast to Hmong-American respondents, 74 percent of whom supported accepting refugees.

Vo said many of the Vietnamese-Americans she spoke with who aren't welcoming of refugees tend to agree with the view that Syrian refugees are dangerous, and they think of themselves as different. That is, they consider themselves to be "good" refugees.

Postwar refugees from Vietnam, she said, considered the Republican Party to be more anti-Communist and — for the largely Catholic immigrants — more socially conservative, with values that aligned with their own. Second-generation Vietnamese-Americans, Vo said, tend to vote for Democratic candidates — as they voted for Barack Obama in 2012.

"They're shifting away from the Republican Party, but not yet ready to commit to Democrats," Wong said. Many Vietnamese-Americans tend to be "big government people" — supporting social services including Obamacare — but aren't necessarily comfortable with the label of "Democrat," she said.

I talked with Steven Mai, a 42-year-old Vietnamese-American engineer and community activist who lives in Garden Grove, Calif. Mai immigrated to the U.S. in 1985. He's a Republican but says he doesn't always vote for GOP candidates. He said he had supported Trump until the Republican candidate criticized the family of Humayun Khan, an American Muslim Army captain who died in Iraq.

"Trump, when he was attacking that family ... I said, 'That's it, that's my final call,' " said Mai, who serves in the California State Military Reserve. "And now I confirmed my belief that yes ... he's just proven over time that he was never a leader."

But Mai's parents feel differently.

"My parents are going to vote for Donald Trump," he said. "Even though I told them their votes can be very dangerous, they said, 'Well, I'm not particularly liking Trump, I just don't like Hillary.'

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