Sen. Dick Lugar is up big over state Treasurer Richard Mourdock in Indiana’s GOP Senate primary, according to an internal poll the Senator’s campaign released.

The poll showed Lugar ahead of Mourdock, 55 percent to 30 percent among likely primary voters. The poll was conducted by Adam Geller at National Research Inc. Previously, Lugar used American Viewpoint to do his polling, but the campaign decided to switch firms, according to a Politico report.

Mourdock is one of the higher-profile tea-party-backed candidates across the country challenging entrenched GOP incumbents in the primary. But his campaign has struggled, mostly because of lackluster fundraising. Mourdock ended last year with $363,000 in the bank compared with Lugar’s $4 million war chest.

Mourdock’s financial disadvantage is evident in the other news from the race out today: Mourdock’s new statewide cable ad attacking Lugar on earmarks. Mourdock’s campaign put $45,000 behind the two-week, relatively small ad buy.

“Every year, Congress finds new ways to spend our money, and sadly, Sen. Lugar went along with it,” Mourdock says in the ad. The 30-second spot also includes a still photo of Lugar with President Barack Obama, likely during the president’s days in the Senate.

The primary is May 8. Roll Call Politics rates this race as Likely Republican.

https://www.youtube.com/watch?v=s4NiLee4JoY&feature=youtu.be