This article is from the archive of our partner National Journal

As president, Bill Clinton signed the Defense of Marriage Act, which authorized states to deny recognition to same-sex marriages performed in other states. As a presidential candidate, Hillary Rodham Clinton launched her 2016 campaign on Sunday with a video that featured two gay men excitedly planning their own same-sex wedding.

That contrast captures a profound shift since Bill Clinton's presidency—not only in American social attitudes, but also in the nature of his party's electoral coalition. If Hillary Clinton wins the Democratic presidential nomination, she will inherit from President Obama a very different coalition than the one that elected her husband. Her great opportunity is to meld the different support that each man mobilized. Her great risk is that she won't be able to re-create quite as much of either man's coalition as she needs to win.

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After Republicans had won five of the previous six presidential elections, Bill Clinton in 1992 regained the White House behind a "New Democrat" agenda that blended traditional liberal goals (like expanding opportunity) with conservative principles (like fiscal restraint and personal responsibility). Many of Clinton's ideas sought to recapture culturally conservative blue-collar, older, rural, and Southern whites who had abandoned Democrats since the 1960s. Clinton didn't entirely succeed, but he stanched the bleeding with culturally conservative whites and simultaneously made inroads with white-collar whites in previously Republican suburbs from New Jersey to California.

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Since Clinton left the White House, the Democratic decline among older and blue-collar whites has continued, even accelerating under Obama. But Obama triumphed twice anyway by assembling a more consistently left-leaning coalition centered on millennials, minorities, and socially liberal whites (especially college-educated and single women). I've called that alignment the "coalition of the ascendant," because its groups are all growing within the electorate, boosting Democrats.

These changes have recast the party. In 1992, white voters without a college education, usually the most socially conservative voters, made up 60 percent of all Americans who identified as Democrats, according to surveys by the nonpartisan Pew Research Center. By 2014, Pew found, those noncollege whites represented just 35 percent of Democrats. Over that same period, college-educated whites grew from 15 to 20 percent of Democrats, and minorities soared from about 25 percent to 45 percent of the party.

This reconfigured Democratic coalition has tilted left since Bill Clinton's day, especially on social issues. In Pew polls, the share of Democrats who think immigrants benefit American society more than they burden it jumped from 32 percent in 1994 to 68 percent by 2014; likewise, the share of Democrats who say society should accept homosexuality rose 20 points over that period (almost double the change among Republicans).

This new party consensus has allowed—and even required—both Obama and Hillary Clinton to replace Bill Clinton's cultural centrism with reliably liberal positions on social issues, including immigration and gay rights. "On virtually every cultural issue, Democrats have staked out very clear positions in ways that Bill Clinton had to do much more gingerly in 1992," says Matt Bennett, senior vice president at Third Way, a centrist Democratic group. "He had to pick his way very carefully through a minefield in ways that she just doesn't." The shift extends throughout the party. In 1996, 32 Democratic senators supported the Defense of Marriage Act; last year, no Democratic senator voted against legislation guaranteeing equal workplace treatment for gays.

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With its buoyant images of same-sex and interracial couples, young parents, and Hispanic brothers speaking in Spanish, Hillary Clinton's announcement video could have doubled as a class photo for the coalition of the ascendant. "There is nothing in that video that says she is going to do the [Bill] Clinton bridge back to culturally conservative whites," says Simon Rosenberg, founder of the Democratic advocacy group NDN.

By contrast, on Tuesday at her first formal campaign event—tellingly held at a small-town Iowa community college—Clinton telegraphed an economic agenda (including expanding access to education and easing the work-life balance) that could appeal to working-class whites. Even today, Democrats can't entirely cede those voters. They remain the decisive voting bloc in aging, preponderantly white Midwest battlegrounds like Ohio, Iowa, and Wisconsin. Obama captured those critical states only by running slightly better among blue-collar and older whites than he did nationally.

Clinton, as a white woman in her 60s, could improve on Obama's Rust Belt performance—but for the same reason, she may struggle to inspire the minority and millennial voters who powered his victories elsewhere, particularly in diversifying Sunbelt battlegrounds like Florida, Virginia, and Colorado. As one senior Democratic strategist notes, the conundrum of Clinton's candidacy is that she could be stronger than Obama in the Rust Belt states, where demography is weakening Democrats, but weaker in the Sunbelt states, where demography is strengthening the party. To win, Hillary Clinton will need some of Obama's skill at mobilizing the Next America—and her husband's knack for connecting with those who feel it is passing them by.

This article is from the archive of our partner National Journal.