It doesn't seem entirely implausible, at least in the short run. But a new look at the numbers, by Ruy Teixeira and Alan Abramowitz, shows that this strategy is almost certainly destined to fail.
One point they note is that a lot of the 'double down on the white vote' talk has been based on an analysis of the 2012 election that is quite misleading - the supposed fact that a lot of white voters simply sat out the 2012 election. These are the 'missing white voters'. But there's a serious amount of self-deception at work here because what's clear from the numbers is that there were in percentage terms about as many 'missing' minority voters.
To put it in a different way, 2012 was simply a low turnout election compared to 2008. The 'missing white voter' theory basically depends on saying, 'Hey, if it had actually been a high turnout election for whites but a low turnout election for non-whites, then things would have been fine.' Then 2012 would have been like 2008. Or to put yet more simply, if completely unrealistic turnout scenarios had offset the growth in the minority vote, there'd be no bad trend.
This is just thinking seriously about the math.
But the other finding of Teixeira's and Abramowitz's analysis is much more interesting.
We might hypothesize that as the minority vote grows, the GOP might get a bigger and bigger share of the white vote. But a deeper look at the numbers shows that this is probably not a realistic expectation. As they argue, "the main reason that the gap between the Democratic margin in the overall electorate and the Democratic margin among white voters has increased over time is not because whites have become more Republican but because nonwhites, who are overwhelmingly Democratic, now make up a larger share of the overall electorate ... In other words, the rapid growth of the very Democratic nonwhite share of the electorate makes it seem like white voters are becoming more Republican than they actually are."
Let me quote at length ...
Viewed from this perspective, the growing gap between the Democratic margin among white voters and the Democratic margin in the overall electorate should probably be viewed by Republican strategists not as an encouraging sign but as a source of considerable concern. What this growing gap really means is that the Democratic presidential candidate can win the national popular vote with a smaller share of the white vote with each successive election. By 2016, nonwhites should make up around 30% of the overall electorate, and the Democratic candidate would be able to win the national popular vote while losing the white vote by 24 percentage points.
None of this means that Democrats can be indifferent to the white vote, especially working class white voters. But the idea that the white vote is getting more Republican sort of a mirage. Whites are not getting more Republican at anything like the rate the minority electorate is growing.
Looking at these numbers, you get a sense of why Republican elites are so desperate to get immigration reform passed with some Republican votes and put the whole thing in the rearview mirror. And yet, the 'double down' theory has taken hold in the GOP House, where reform will likely die.