Only 42% of Asian Americans are Christians. Only 24% of Asian American voters supported Mitt Romney in 2012.

So maybe Republicans, who are currently seeking ways to expand their non-white voter base, should stop demanding that people should say "Merry Christmas" instead of "Happy Holidays."

Here's a shirt recently sold by the National Republican Congressional Committee. It reads "'Happy Holidays' is what liberals say." An NRCC spokesperson told Buzzfeed the shirt has sold out.

The shirt is printed in Comic Sans, but that's not the biggest problem with it.

Here's the thing: Some people celebrate Christmas and some don't. It's fine to say "Merry Christmas." But sometimes, a speaker wants to be especially mindful of the fact that not all of his or her listeners celebrate Christmas, so he or she says "Happy Holidays."

Why should Republicans have a problem with that? When Republicans say they have a problem with it, what message are they sending to non-Christian voters?

Most voters are Christian, so a pro-Christmas position seems like it should be popular. But Republicans don't understand how their anti-outsider messages aggregate.

Most voters are straight, so opposition to gay marriage shouldn't be an electoral problem. Most voters aren't Mexican-Americans, so they shouldn't be too bothered by thinly-veiled (or unveiled) anti-Mexican messaging on immigration.

Add these things all together, and you get a political party that looks like it's engaged in interest group politics for straight non-Hispanic white Christians. That's not too appealing to the increasing share of voters who aren't straight non-Hispanic white Christians.

Mitt Romney took just 24% of the Asian vote in 2012, a worse performance than among Hispanics. That was even though Asians have higher family incomes and educational achievement than whites, and lower rates of out-of-wedlock birth.

Republicans' typical explanation of their poor performance with blacks and Hispanics (a policy platform that alienates groups disproportionately likely to depend on government services) can't explain Republicans' Asian gap. But the party's perceived hostility toward out-groups can.

If Republicans want to be a viable political party in an increasingly diverse country, they need to drop their opposition to pluralism. They can start by ending the whining about the "War on Christmas."