This is the worst omen for Dick Lugar in a slew of bad omens this week.

The SuperPAC which has dumped $600,000 of advertising into the Indianapolis market is pulling out of the race:

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.

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.

While Lugar has a lot of money in the bank, this is a sign that the Republican establishment has given up on him and doesn’t want to damage Mourdock for the general election:

Lugar still has a big warchest to draw from, so the loss of ads against Mourdock won’t hurt him that badly in the air war. But this is the latest sign that the race is slipping away from the six-term senator, who has been badly damaged after it was revealed he’s lived in Washington, D.C. for decades and is a top target of many conservative groups.

The race seems to be slipping away from Lugar and the American Action Network may want to avoid inflicting any more damage on Mourdock, the likely nominee, ahead of what could be a competitive general election race against Rep. Joe Donnelly (D-Ind.).

Lugar still has John McCain, Pat Boone and Mitch Daniels (barely) stumping for him.  It has come to that.