Two years ago I wrote that the Democrats were a more united party than the Republicans, despite covering a broader ideological spectrum. But last night's Iowa caucuses exposed a stark generational and ideological fault line in the Democratic party that may not be easy to bridge.
Supporters of both the Sanders and Clinton campaigns complain about online vitriol from the rival camp. But that was also true with the Obama and Clinton camps in 2008. Campaigns can't control supporters. And such behavior proved inconsequential to uniting the party for the general.
It may be different in 2016. Obama and Clinton had their differences – the Iraq war and diplomatic strategy the most significant – but the ideological distance between them was not fundamental. They differed on the war vote, but Clinton supporters were not neoconservative warmongers. They could get behind Obama's foreign policy without much convincing.
Clinton and Sanders, however, represent two entirely different factions of the party. Yes, they both point in the same rough ideological direction. But the Sanders agenda goes much farther and much faster. And it is premised on a completely different strategy for enacting change: mobilizing the grassroots instead of working the system from the inside.
Clinton and Sanders have been perfectly respectable to each other – far more than Obama and Clinton were eight years ago. But will every Sanders voter so quickly agree to support a candidate with Wall Street donors? Who opposes single-payer and limits on bank size? Who emphasizes compromise with Republicans?
As I explain in Politico Magazine today, the likelihood of a protracted primary fought along these ideological lines brings with it great risk, similar to the 1980 primary between Jimmy Carter and Ted Kennedy.
It will be incumbent upon Clinton and Sanders to emphasize civil disagreement, but even that may not be enough to prevent lost voters in November.
Which only matters if the general election is really close.
Which it might be.