The real significance of a Lugar loss, though, would extend far beyond November. The fact that he’s now fighting for his political life in a GOP primary is a reflection of the endurance of the Tea Party phenomenon. The term itself may feel tired and even dated, a relic from 2009 or 2010, but it’s really just a colorful synonym for “Republican Party base.” And as Lugar’s perilous standing shows, that base is waging the same kind of purity crusade in 2012 that it did in 2010.

The difference is that there are fewer targets this time around, which makes sense: Dozens of Tea Party-aligned Republicans won House seats in ’10, moving the center of gravity in that chamber about as far to the right as it’s ever been. But the bigger success the Tea Party had in ’10 was that it got into the head of every Republican on Capitol Hill. Watching Republican incumbents like Bob Inglis, Bob Bennett and Mike Castle lose out to little-known – and, in some cases, glaringly unqualified – Tea Party-backed challengers, delivered a clear message to Republican lawmakers: If you stray from our absolutist, compromise-phobic stance even once, you’ll be next.