Political factions rarely die. They fade away for a while only to reappear in new forms. The Obama-Clinton divide of 2008 may be hidden of late, but some similar fissure may well reemerge in 2016.

One hidden divide is generational. Obama’s victory over Clinton in 2008 seemed to be almost a passing-the-torch moment from one American era to the next. In a much-discussed magazine article in late 2007—just as Obama was gaining ground on Clinton—commentator Andrew Sullivan argued that Obama’s candidacy could allow the country to say “Goodbye to All That,” meaning the Baby Boomer-inspired cultural and political wars of the late 20th century. A Clinton nomination would put the presidency, and the Democratic Party, squarely back in Boomer hands. Which raises another comparison to Nixon: His presidential nominations in 1960 and 1968 were broken up by the far more conservative campaign of Barry Goldwater in 1964. After the party embraced the right, it scurried back to the establishment four years later. A Clinton nomination, post-Obama, would be another “back to the future” moment when the party, after a shift to Obama’s promise of a new kind of politics, turned back the clock to the Clintons. Still, the generational argument is one available to a possible Clinton challanger.