Lt. Gov. Jim Risch (R) led former Rep. Larry LaRocco (D) by 15 points in the race to replace retiring Sen. Larry Craig (R), according to a poll conducted six weeks ago by LaRocco’s pollster.

Risch, who beat LaRocco by 19 points in the 2006 lieutenant governor’s race, was up on the former Congressman 43 percent to 28 percent, with 18 percent undecided. Rancher Rex Rammel, running as an Independent, registered with 6 percent.

The survey of 500 likely voters was conducted May 20-25 by Lake Research Partners, and had an error margin of 4.5 points.

However, the LaRocco campaign believes the poll provided several glimmers of hope. Among its other findings:

• President Bush’s disapproval rating in Idaho was at 54 percent.

• Risch’s favorable rating was at 44 percent, while LaRocco’s was at 29 percent. Risch’s unfavorable was at 23 percent, while LaRocco’s was at 20 percent.

• Risch’s job-approval rating as lieutenant governor was 49 percent (“excellent” or “good”); 31 percent rated him “fair” or “poor.”

• The presumptive presidential nominees were near equal in their favorable ratings, with Sen. John McCain (R-Ariz.) registering 54 percent and Sen. Barack Obama (D-Ill.) registering 50 percent.