Delta County Commissioner Wayne Wolf, a Western Slope Republican, is in the race to replace Sen. Wayne Allard, reports the Denver Post. Wolf, a rancher and former teacher, is the second serious Republican candidate in the race, along with ex-Rep. Bob Schaffer.

Wolf's entry shows the fundamental geographic divide in the state. Sources say his reputation is as a conservative, like Schaffer, but Delta County is on the state's western slope. Shaffer represented the state's 4th Congressional District, on the east side of the state, during his three terms in Washington.

Schaffer remains the favorite to win the GOP primary, though whoever takes the prize will face an uphill battle against likely Democratic nominee Rep. Mark Udall. Udall has prepared for the race for several years, and will be difficult for the Republican nominee to compete with financially.

For more background, see my piece on recent population shifts as they effect the Colorado landscape going into 2008.