For the second straight month, Democrat Mark Udall holds a three-point edge over Republican Bob Schaffer in the race to become Colorado’s next United States Senator. The latest Rasmussen Reports telephone survey in Colorado found Udall attracting 45% of the vote while Schaffer earns 42%. A month ago, Udall was up 46% to 43%. Two months ago, it was Schaffer with a statistically insignificant one point lead.

This is the fourth straight Rasmussen Reports election poll to find the two candidates within three points of each other.

Both men have seen their popularity slide a bit over the past month. Udall is now viewed favorably by 48%, down four percentage points from 52% a month ago. Schaffer is now viewed favorably by 47%, down six from a month ago.

Those figures include 20% with a Very Favorable opinion of Udall and 14% with a Very Unfavorable opinion of the Democrat. Schaffer earns Very Favorable reviews from 12% and Very Unfavorable ratings from 15%.

Udall leads by eight points among women but trails by three among men. Schaffer attracts 80% of Republicans while Udall is supported by 84% of Democrats. Among unaffiliated voters, the candidates are even.

Thirty-eight percent (38%) of Colorado voters say the economy is the most important voting issue of Election 2008. Twenty percent (20%) say it’s the War on Terror while 12% name immigration.

Voters who see the economy as the top issue are evenly divided between Udall and Schaffer. Those who see Iraq as the highest priority strongly prefer Udall. Schaffer dominates among those who see immigration as most important.

Udall and Schaffer are vying for an open senate seat vacated by retiring Republican Senator Wayne Allard. It is one of several seats held by Republicans that Democrats believe could increase their majority status in the Senate. Other potentially vulnerable Republican seats include those in Virginia, Minnesota, New Mexico, Alaska and New Hampshire.

Rasmussen Markets data shows the Democrats are favored to win the Colorado senate race (current prices: Democrat %; Republican %) Numbers in this paragraph are from a prediction market, not a poll. We invite you to participate in the Rasmussen Markets. It costs nothing to join and add your voice to the collective wisdom of the market.

In the race for Colorado’s Electoral College votes, John McCain and Barack Obama are locked in a tight match-up. . McCain leads Clinton by double digits.

See survey questions and toplines. Crosstabs are available for Premium Members only.