The American Action Network can read the polls, and what they see is Senator Dick Lugar in Indiana likely defeated in the primary on May 8.

The Super Pac, which has been supporting incumbent GOP senators against primary challengers, pulled the plug and walked away, leaving Lugar to his own devices.

Politico:

The American Action Network is pulling out of the Indiana GOP Senate primary, dropping its efforts on behalf of embattled Sen. Dick Lugar less than two weeks before the May 8 election, sources told POLITICO.

Dan Conston, a spokesman for AAN, explained: "We've decided we're going to let this race play out."

The group has already begun to pull its TV dollars; no further ads will run after Tuesday and digital advertising in the race has stopped effective immediately.

AAN, one of the top Republican independent spending groups, had spent heavily in the Indianapolis media market in recent weeks. The organization has pummeled Lugar's challenger, state Treasurer Richard Mourdock, with tough ads questioning his business and tax practices, and his performance in office.

Republicans have told me the ads appear to have helped move the needle in Indianapolis, but the sense across the party is that the race has broken in Mourdock's direction throughout Indiana.

For a group like AAN, that would raise the question of whether it makes sense to keep going after a man who looks likely to be the Republican candidate against Democratic Rep. Joe Donnelly. Lugar may have been the GOP's strongest general election candidate, but if he is beyond recovery -- or close -- then the next-best thing is a relatively undamaged Mourdock.

Mourdock is evidently more palatable to the tea party than Lugar, but if the 6 term senator loses, the race goes from "strong GOP hold" to "toss up" or slightly leaning GOP. Donnelly, a former congressman, has statewide name recognition and will give Mourdock all he can handle in what is usually a solid GOP state.

But Mourdock will be extremely well financed and has proven to be a statewide vote getter. Even without Lugar, it still looks pretty good for Republicans.