Sean Trende's intriguing three-part thought experiment on the future of the Republican electoral coalition is admirably well-researched and appealingly counterintuitive. It also encourages Republicans to commit suicide.

Writing at RealClearPolitics.com, Trende said Republicans might opt out of immigration reform (which many don't like to begin with) and forget about making amends with Hispanics. Instead, he said, they could focus on rallying "missing white voters" who sat out the last election.

Trende doesn't buy the common argument, repeated at Bloomberg View and elsewhere, that Republicans need the issue off the table in order to begin competing for Hispanic and Asian votes. "This is extraordinarily sloppy thinking -- groupthink at its worst," he writes.

Trende, a proper numbers guy, dutifully runs the data. He finds perhaps 6.5 million disenchanted white voters, many of them fitting the profile of Ross Perot supporters from the 1990s, to be the low-hanging Republican fruit. If the black vote recedes to a more typical level after the first black president leaves office, and Hispanic voters muddle along in typically low-turnout fashion, Republicans can still win nationally without making concessions to 21st-century demography.

I get his point. Under favorable circumstances, the numbers are there. But the racial composition of the Republican Party isn't just a numbers game; it's a crisis of legitimacy. And further pursuit of whiteness is a jarringly wrong-headed strategy. In a multiracial nation, growing ever more diverse, how will nonwhites interpret the motives, aspirations and identity of a political party that insists on staking its claim to power on a racially exclusive base?

Republicans' self-segregation isn't a product of happenstance. The party willed it, and for years reaped its benefits. But neither is it necessarily a permanent condition. President George W. Bush seemed to be moving the party toward inclusion, capturing four in 10 Hispanic votes and earning his way to a double-digit showing among blacks in 2004. That's only nine years ago but it counts as a different geological era -- before Palinism, before the Tea Party, before a frightened army in retreat began waging hyperpartisan warfare.

Why do Hispanics, Asians and blacks all vote Democratic, anyway? Hispanics are the lowest-earning, and least educated, ethnic group in the nation. Asians are at the top of both the income and education scales. Yet both groups voted for Barack Obama by roughly the same 2-to-1 margin. Are Republicans interested in understanding why?

Trende says political coalitions are "fluid." They also can freeze. Blacks were voting overwhelmingly Democratic long before Obama was elected. Unless Republicans devise a way to magically erase all memories of their war on everything Obama, the Democratic bond with black voters won't sever anytime soon.

Which only hints at the real peril of chasing "missing white voters." Republican policies already cater to an increasingly narrow tranche of American society: the rich and the old (who, not coincidentally, happen also to be white). When they wax nostalgic over the era of institutional racism and sexism, it sounds like moral obtuseness to most younger, more diverse voters. And so it is. How long before Republicans put themselves out of reach of most Asians and Hispanics as they have with blacks?

There is no reason conservatism can't find its footing in a multiracial century. Yet Republicans lack the confidence to test the proposition, opting instead for the kind of voter suppression tactics designed, like these proposals in North Carolina, to stifle the nonwhite vote rather than win it. Moral and political legitimacy need to be constantly replenished. The past is another country. Republicans should stop representing it.

(Francis Wilkinson is a member of the Bloomberg View editorial board. Follow him on Twitter.)