It is a challenge that runs throughout the nation’s industrial heartland, in farm states and across the South, after a half-century of economic, demographic and cultural shifts that have reshaped the electorate. Even in places like Michigan, where it has been decades since union membership lists readily predicted Democratic votes, many in the party pay so little attention to white working-class men that it suggests they have effectively given up on converting them.

Not Mr. Houston. “There’s a whole cadre of us — of young, white men political leaders in Oakland County — who are saying, ‘We can’t just write off 30-year-old to 40-year-old guys, let alone anyone who’s older.’ ”

So Mr. Houston and like-minded Democrats are working to deploy new, data-driven targeting tools to get the message to white men that the party is more in sync with them than they might think. “We can tell you to the number how many we need and where they live,” said Matt Canter, the deputy executive director of the Democratic Senatorial Campaign Committee.

No Democratic presidential candidate has won a majority of white men since Lyndon B. Johnson in 1964. Jimmy Carter, Bill Clinton and Barack Obama all prevailed with support of the so-called rising electorate of women, especially single women, and minorities. But fewer of those voters typically participate in midterm elections, making the votes of white men more potent and the struggle of Democrats for 2014 clear.

“Realistically, winning votes from working-class white men has just been a very tough political challenge for Democrats,” said Geoff Garin, a Democratic pollster. With demographic trends favoring Democrats nationally and in many states, strategists say it makes sense to concentrate resources on mobilizing women, young people, Hispanics, blacks and other minority voters.