American Future Fund, an independent conservative-leaning advocacy group, is extending its advertising campaign to Colorado.

On Wednesday the organization is launching a 60-second radio spot hitting U.S. Rep. and U.S. Senate candidate Mark Udall (D-Boulder) on the issue of oil exploration. The ad is set to run for two weeks statewide, according to a spokesman. The amount of the initial ad buy is $130,000.

“Gas prices are at an all-time high. But Congress -- led by Nancy Pelosi and Mark Udall -- has blocked real solutions,” an announcer says in the ad, which goes on to note the availability of oil reserves in western Colorado.

“But Mark Udall has repeatedly voted against exploration – blocking development of our vast energy resources. That’s more of the politics of delay that have driven gas to four bucks a gallon.

"In fact, Udall has voted to delay energy exploration at least thirty-four times. Coloradans need real solutions on gas prices.

“Call Mark Udall: 303-650-7820,” the spot concludes. “Tell him to stop delaying energy exploration and support HR 6108 – for real solutions.”

American Future Fund’s decision to enter the Colorado contest means that the organization has now waded into two high-profile Senate races. In March, upon announcing its intentions to play a role in the 2008 campaign, the organization aired a television spot supporting U.S. Sen. Norm Coleman (R-Minn.).

American Future Fund, which is staffed by top GOP operatives Larry McCarthy, Ed Tobin, and Jan van Lohuizen, is for the time being something of a Senate-focused counterpart to Freedom’s Watch, the independent conservative organization that is running radio ads and robo calls in House races across the country. Freedom’s Watch has indicated its intention to participate in the Senate arena but has yet to air any paid media.

The release of the ad comes as Senate Republican leaders are voicing confidence in domestic drilling as a campaign issue this fall.

“From a political standpoint, Republicans are on the right side of this issue and Democrats are on the wrong side,” National Republican Senatorial Committee chair and U.S. Sen. John Ensign (R-NV) said on a conference call with reporters Tuesday. “Bottom line: Across the board, this is becoming a very good issue for us.”

Udall is facing off against Republican Bob Schaffer for the seat of retiring U.S. Sen. Wayne Allard (R-Fort Collins).