Rep. Dean Heller (R-Nev.) would hold a commanding lead over Sen. John Ensign (R-Nev.) in a Republican primary, according to an internal poll from the Heller camp. 

Heller leads Ensign 53 percent to 38 in the survey, conducted late last month by the GOP firm the Tarrance Group. 

Pollster Dave Sackett writes in the memo that Ensign "is so badly damaged that he is already trailing on a ballot test against Dean Heller by 15 points." The poll found just 9 percent of likely Republican voters undecided in a potential Heller-Ensign match-up. 

The release of the numbers is an indication that Heller is moving toward a primary challenge to Ensign, who is still forging ahead with his reelection campaign. Despite the abysmal poll numbers and the desire among national Republicans to have someone else on the ticket next year, Ensign is continuing to ramp up his fundraising efforts.   

Ensign told The Ballot Box last week that the response to his early campaign moves in Nevada has been positive and said he was confident he'll raise enough money to compete. 

"I think most of the money is going to come in in the second quarter, but we're getting it all scheduled, which is a very positive sign," he said. "We are focused on fundraising right now, and doing my job for the people of Nevada trying to help the economy, because it's in dire shape out there."

Still, Heller's internal numbers mirror some of the public polling already conducted on the race, which shows Ensign trailing badly. 

"Strongly paralleling the untenable situation that faced former Gov. Jim Gibbons in 2010, a plurality of likely Republican primary voters in the state of Nevada believe that Sen. Ensign does not deserve reelection and that it is time for a new person," Heller's pollster wrote in the memo, making the argument that Ensign's scandal has left him too damaged to win in 2012.

With self-identified conservatives, Heller blows Ensign away, taking 62 percent of the vote. 

The poll also tested Heller's strength in a crowded primary field, which included potential candidates Sharron Angle, Danny Tarkanian and John Chachis. In a five-way primary race, Heller still led by 16 points.