Whole lot of stories about the tea party having fizzled will need to be rewritten if Mourdock pulls this off. Remember, as of two months ago, he was 25 points ahead.

Indiana state treasurer Richard Mourdock leads Senator Dick Lugar by one point according to a poll commissioned by the Mourdock campaign. Conducted between April 16 and 17 by the firm McLaughlin and Associates, the poll surveyed 400 likely Republican primary voters and found Mourdock in the lead, 42–41, against Lugar. The poll had a 4.9 percent margin of error.

Since January, Lugar’s favorability rating has fallen ten points, from 57 to 47 percent, while Mourdock’s has risen by eleven, from 35 to 46 percent. “These results clearly demonstrate that Richard Mourdock has the momentum to win,” a memo from pollsters John McLaughlin and Stuart Polk notes.

Mourdock and Lugar held a televised debate just six days ago, so if the internal poll is correct and his numbers are surging, there’s one likely explanation — Indianans finally had a good look at him and liked what they saw. I’m amazed, frankly, that Lugar would do him the favor of raising his name recognition by sharing a stage with him. He’s been winning walkover primaries for more than 30 years; if he ignored Mourdock entirely, it’s a safe bet that some chunk of Indiana Republicans wouldn’t be able to pick RM out of a lineup and would pull the lever reflexively for the incumbent on election day. In fact, according to the Indy Star, while Mourdock outraised Lugar in the last quarter, nearly three-quarters of his donations came from out of state compared to a little more than half for Lugar — an ironic counterpoint to the charge that Lugar’s left Indiana behind by going native inside the Beltway.

Anyway. They had a debate and Mourdock’s suddenly outraising the incumbent and even establishment conservative magazines like National Review are ready to trade Lugar in for new blood. What’s a six-term incumbent who’s in trouble to do? Why, call in the big guns:

Sen. Dick Lugar (R-Ind.) will roll out two heavy-hitting surrogates in his next round of ads: Indiana Gov. Mitch Daniels (R) and Sen. John McCain (R-Ariz.).

Daniels is one of the most popular politicians in Indiana, and is especially beloved by the Republican base. He told The Hill in September that Lugar was a “mentor,” “icon” and “extraordinary public servant” — his support could help Lugar in a big way.

Hard to believe Mourdock can survive both Lugar’s institutional advantage and an endorsement from Mitch the Knife, but since this is tea partiers’ best shot at flexing conservative muscle this year, maybe they’ll take it as a challenge. I’ve got nothing against Lugar, who by all accounts is a lovely man, but the careerist inertia involved in an 80-year-old fighting desperately for six more years at a job he’s held since the late 1970s makes me shudder. If this sad, sclerotic spectacle doesn’t make you think twice about term limits, nothing will.