If this continues to be the Vermont senator’s approach, Sanders will be more of a help to Clinton’s presidential chances than he will be to his own.

The first bonus that Sanders provides for Clinton, say her supporters, is that he becomes a foil. One of Clinton’s Democratic allies in Congress explained that with a country that prefers general election candidates closer to the middle, Sanders will always offer proof that Clinton is not really that far left. He does for Clinton what Howard Dean did for John Kerry in 2004.....

In 2012 Rep. Ron Paul and Mitt Romney had a symbiotic relationship in the Republican campaign. Paul elevated his own profile and gave his voters an outlet, but he never pointed out the yawning gaps between what he claimed to believe so deeply and the positions of the man who was on his way to being the party’s inevitable nominee. It’s way too early to see if Sanders will play the same role for Clinton, but it has started out that way.

Sanders is such a long shot that those who share his views might be OK with the consolation prize of imitation from Clinton. But if her move to the left is simply rhetorical, she can shed that rhetoric in the general election as candidates often do. This would be another reason for Sanders to press his case with more definition.