Scher mentions Sen. Blanche Lincoln, who lost a general election after being challenged unsuccessfully in the primary. But there is no compelling evidence that Lincoln lost because she was primaried -- and none at all to indicate that she lost because she adopted more progressive positions.
We do know that Sen. Lincoln pushed forcefully for an amendment to the Dodd/Frank financial reform bill. The "Lincoln Amendment" prevents financial institutions from accessing favorable Federal Reserve credit if they conduct credit swaps. While it's not perfect, this amendment made the bill stronger -- and there are many who attribute Lincoln's change of heart to a primary challenge from the left.
Score one for primaries.
When The Going Gets Nasty, The Nasty Get Going
Scher also argues that Democrats "have suffered the consequences of failed primary challenges themselves," pointing to the 2006 attempt to defeat Joe Lieberman. It's true that Lieberman lost the Democratic primary before ultimately winning the general election that year -- but a battalion of senior party heavyweights, including Bill Clinton, stepped in on his behalf.
Lieberman's was an exceptional case. The election was largely driven by the surprising weakness of his Democratic challenger, while any vindictive after-effects can be attributed his own singularly unappealing personality.
Besides, do we really know that Lieberman wouldn't have become precisely the irritant he became had he gone unchallenged in the primary? After all, his obstructionist impact on Obama's most important first-term legislation was indistinguishable from that of other Blue Dog Democrats.
There is a compelling case to be made, in fact, for arguing that the left should have challenged more of Lieberman's "centrist" colleagues. Such challenges might have made the two key pieces of legislation from Obama's first term -- the Affordable Care Act and Dodd/Frank -- more progressive than they ultimately became.
Then there is the example of Zephyr Teachout herself. Scher describes her primary challenge to Cuomo as "a losing campaign," but that misses the big picture. Cuomo treated the left with lordly contempt during his last term, a stance that rendered him indistinguishable from most of his fellow corporatist Democrats. (Remember when White House Chief of Staff Rahm Emanuel called progressives "f**kin' retards" -- and President Obama never chided him for it?)
Cuomo's attitude changed when progressives became a serious threat to his plans. Teachout's candidacy, together with the threat of losing the Working Families Party line on the ballot, forced Cuomo to make significant commitments to the left. New York's ballot rules are unusual, but Cuomo's concession can be taken as another policy victory for progressive challengers.
Of course, it remains to be seen whether Cuomo will honor those commitments. But if he welshes on a public pledge, it certainly can't be argued that a softer approach would've been more successful.
Familiarity breeds contempt, as Emanuel's insult demonstrated. One of the lessons from the Cuomo challengers is this: Pushback can generate more respectful attention for the left.
Run, lefties, run
Scher is at his most persuasive when he is arguing that, despite their own occasionally fatalistic perceptions, progressives "already possess a significant amount of influence within the Democratic Party." He's right about that, and progressives would do well to remember that more often. But, contra Scher, the differences within the Democratic Party can be quite acrimonious at times.