The Tea Party notched its biggest win since 2010 — and perhaps ever — on Tuesday, unseating longtime Sen. Dick Lugar (R) in Indiana's Republican primary election. Replacing Lugar on November's ballot will be state Treasurer Richard Mourdock, who was backed by local Tea Party groups and a range of deep-pocketed conservative outside groups. The moderate Lugar, who's been in the Senate since 1977, was considered a shoo-in for the general election, while the relatively unknown conservative Mourdock faces a tough fight against Rep. Joe Donnelly (D). Republicans need to pick up four seats to gain control of the Senate. Has the Tea Party put that majority out of reach by endangering a once-safe seat?

Democrats really could take Lugar's seat: Tea Partiers, the NRA, and other pro-GOP groups just handed the Democrats a huge gift, says Melinda Henneberger at The Washington Post. Donnelly has a real shot at beating the divisive Mourdock, and some polls even show him starting the race with a slim lead. Yes, Indiana is pretty conservative, but as "a pro-gun, pro-life, pro-Keystone pipeline, anti-illegal immigration, and anti-climate change legislation Blue Dog, Donnelly has a lot in common with Lugar" — without Lugar's baggage.
"Joe Donnelly, the Democrat... is a winner today, too"

Mourdock is the heavy favorite to win: Indiana isn't just conservative, it's "trending redder, and it would be a surprise if the GOP lost this Senate seat," says Richard K. Barry at The Reaction. Democrats would love for Mourdock to be "the kind of crazy right-winger who beat himself, much as Christine O'Donnell did in Delaware" in 2010. But no, he's won statewide office twice in six years, and unlike O'Donnell and other unstable Tea Party "pretenders," Mourdock has shown himself to be a solid, disciplined campaigner.
"Say goodnight, Dick Lugar"

The race is now a tossup: Mourdock won "a low-turnout election marked by voter anger and non-voter apathy," says Matthew Tully at The Indianapolis Star. Things will be different in November, with the electorate "much larger, more diverse, and less conservative than Tuesday's, giving Democrats a chance." The brutal Mourdock-Donnelly race will be a sight to behold, with control of the Senate at stake, "but for today, the news is the end of Lugar's long political career." On everything from foreign policy to bipartisan comity, "the Senate will be a lesser place because of his absence."
"Results tough on Lugar, nation"