While the party was drawing more of its money from an elite group of the wealthy, it was drawing more votes from working-class and middle-income whites. Between 2008 and 2012, according to the Pew Research Center, more lower-income and less-educated white voters shifted their allegiance to Republicans.

These voters had fled the Democratic Party and were angry at Mr. Obama, whom they believed did not have their interests at heart. But not all of them were deeply conservative; many did not think about politics in ideological terms at all. A 2011 Pew survey called them the “Disaffecteds.”

Older white voters with little education beyond high school, under enormous economic stress, the Disaffecteds surged to the Republican Party early in Mr. Obama’s first term. But they were as cynical about business as they were about government. They viewed immigrants as a burden and an economic threat. They opposed free trade more than any other group in the country.

Some conservative intellectuals warned that the party was headed for trouble. Republicans had become too identified with big business and the wealthy — their donor class. They urged Republican lawmakers to embrace policies that could have a more direct impact on pay and economic prospects for these voters: wage subsidies, relocation aid to the long-term unemployed, even targeted infrastructure spending. But much of the party’s agenda remained frozen.

“They figured, ‘These are conservative voters, anti-Obama voters. We’ll give them the same policies we’ve always given them,’” said James Pethokoukis, a fellow at the American Enterprise Institute. “High-earner tax cuts, which people are skeptical of; business tax cuts, even though these businesses seem to be doing great. It didn’t resonate with the problems in their lives.”