May 21, 2015 One of the most underappreciated stories in recent years is the deterioration of the Democratic bench under President Obama's tenure in office. The party has become much more ideologically homogenous, losing most of its moderate wing as a result of the last two disastrous midterm elections. By one new catch-all measure, a party-strength index introduced by RealClearPolitics analysts Sean Trende and David Byler, Democrats are in their worst position since 1928. That dynamic has manifested itself in the Democratic presidential contest, where the bench is so barren that a flawed Hillary Clinton is barreling to an uncontested nomination.

But less attention has been paid to how the shrinking number of Democratic officeholders in the House and in statewide offices is affecting the party's Senate races. It's awfully unusual to see how dependent Democrats are in relying on former losing candidates as their standard-bearers in 2016. Wisconsin's Russ Feingold, Pennsylvania's Joe Sestak, Indiana's Baron Hill, and Ohio's Ted Strickland all ran underwhelming campaigns in losing office in 2010—and are looking to return to politics six years later.