We are living in the twilight of the great culture war — a forty-year battle over social issues that helped separate white voters, both of the working class and the middle class, from their natural allies in the Democratic Party.

The culture war is winding down mainly because of demographic changes, as Ruy Teixeira pointed out in a 2009 study published by the Center for American Progress. Younger Americans are more tolerant on issues of race and sexuality, and the old fault lines of the 1960s and 1970s simply don’t produce the electoral earthquakes they once did. Also, crime is way down, as are welfare rolls.

These days, social issues seem more likely to hurt Republicans than Democrats. Witness the damage done by U.S. Rep. Todd Akin of Missouri, a Republican running for the Senate there, with his remark on rape, and a series of other gender flaps over the past year that have hurt Republicans. Even gay marriage, a potent GOP weapon in 2004, is now barely mentioned by Republicans — lest they appear intolerant and alienate moderate voters who already worry about the GOP’s extremism.

Young evangelical voters, once the foot soldiers of a socially right-wing GOP, are becoming more tolerant, according to some reports. Meanwhile, the Archie Bunker generation of whites — those who came of age before the 1960s — is starting to die off, becoming a much smaller slice of the electorate.

To be sure, conservatives are doing their best to keep the old wedge issues alive. Romney has been hammering Obama on “gutting welfare reform” for months now (charges that are false, by the way) and the basic frame of “makers vs. takers” is essentially the same paranoid story of “us” versus “them” that the right has been peddling since the beginning of time.

But the culture war just isn’t going to ever burn as hot as it once did. So what will happen to American politics if the old wedge issues fade away? Economic issues will move more front and center, along with a broader debate about the role of government — pretty much the election we’re having this year and also had in 2008.

This is a good thing for progressives. Surveys show that the white working-class voters are more liberal on economic issues than better-educated, higher-income voters. For example, a 2009 study by the Center for American Progress documented that difference:

Americans with a high school education or less are much more likely than post-graduate educated elites to believe the following:

• Government policies too often serve the interests of corporations and the wealthy
• Government has a responsibility to provide financial support for the poor, the sick, and the elderly
• Government must step in to protect the national economy when the market fails
• The gap between rich and poor should be reduced, even if it means higher taxes for the wealthy
• Rich people like to believe they have made it on their own, but in reality society has contributed greatly to their wealth
• Labor unions play a positive role in our economy

If white working-class voters more fully return to the Democratic Party as the culture war ends, the effect could be to pull that party to the left — along with American politics writ large.

David Callahan is a senior fellow at Demos, a New York-based think tank, and editor of Demos’ blog, Policyshop.net, where this piece first appeared.