As I noted this morning, the argument that Republicans don’t really need to improve their standing much among Latinos to be competitive in national elections is gaining real ground among Republicans — posing a serious threat to immigration reform. The emerging case is that Republicans mainly need to do even better among whites — by doing a better job energizing white supporters and by bringing in more “missing” white voters who might be inclined to vote Republican — thus relieving them of the inconvenient need to alienate their base with anything that might persuade Latinos to give their party a second look.

Today Nate Cohn published what may be the most comprehensive piece yet attempting to debunk this notion, which was perhaps best laid out by Sean Trende the other day. Cohn’s piece is well worth reading in full, but here is the summary version:

1) If Republicans are going to increase their performance among white voters even further, they will have to moderate on social issues in ways that will be discomfiting to the base in any case; Republicans will have to “pick their poison.”

2) The whites-only theory of the case depends on the GOP continuing to improve its standing among whites going forward. While this is currently happening, GOP gains among them are largely regional — focused in the south and in Appalachia. At the same time, Democrats may be gaining among whites outside these regions, which, if it continues, could “cement the Democratic edge in the Electoral College.” This is being exacerbated by the aforementioned refusal to moderate on cultural issues — particularly in key suburban areas.

3) The notion that the GOP’s future hopes turn largely on boosting turnout among “missing white voters” who didn’t turn out in 2012 is complicated by the fact that many of these voters might vote Democratic. This could be made even worse by the fact that many missing whites were young voters. Over time, if the next generation of young voters is as liberal as this one, it could push the national white voter further leftward. Cohn concludes:

Conservatives take solace in the possibility that they could win with gains through whites, presumably on the assumption that the changes needed for gains among non-southern white voters will be less painful than embracing immigration reform. To the extent that this assumption is informed by the view that the GOP is making broad, steady gains among white voters, it is wrong. The GOP has a tough road ahead.

I’m no demographics expert, so I don’t feel qualified to say who is right. But one fair conclusion to be drawn from Cohn’s analysis is that the “bank on winning more whites” strategy seems dependent on a number of unpredictable factors breaking the GOP’s way in a sustained way over time. What’s more, it also seems to presuppose — putting aside raw demographic questions about Latino and white vote shares — that there is no larger risk in failing to develop a more inclusive and tolerant overall image for the party.

In other words, it seems like an epic gamble. But judging by the GOP’s continuing embrace of hidebound positions on issues that many Republicans themselves recognize a need to evolve upon, it increasingly appears to be a risk the party is prepared to take.

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Greg Sargent writes The Plum Line blog, a reported opinion blog with a liberal slant -- what you might call “opinionated reporting” from the left.