Fourth Congressional District Democratic nominee Betsy Markey will likely need 60-percent-plus support from unaffiliated voters to defeat U.S. Rep. Marilyn Musgrave (R-Fort Morgan), according to an analysis set up by a Colorado State University professor.

CSU political science professor Kyle Saunders examined the vote totals from the 2006 race between Musgrave and Democrat Angie Paccione, according to a blog post by the Fort Collins Coloradoan's Bob Moore.

In the analysis, Saunders split third-party candidate Eric Eidsness' vote total that year evenly between Democrats and Republicans.

Under these conditions, Saunders found that Markey needs to receive about 56 percent of the vote in Larimer County, 58 percent of the Boulder County vote, 47 percent in Weld County, and 33 percent in the rest of the district. All of those numbers are 2-3 percentage points more than Paccione's 2006 vote percentage plus half of Eidsness'.

So from where is Markey going to get those voters? Moore says most likely from unaffiliated voters, who make up just over a third of all the 4th District's voters.

Moore ran a scenario in which 90 percent of registered Democrats and Republicans in the district vote, as well as 85 percent of unaffiliated voters. If Markey and Musgrave each win over about 90 percent of their respective party's voters, that means Markey needs 63 percent of the unaffiliated vote to win.

As Moore points out, that's not an insurmountable task for Markey: the lone public poll in the race, conducted in late August, showed Markey winning the unaffiliated vote 59 percent to 29 percent.

Of course, Markey would need less unaffiliated support if she draws more Republicans than Musgrave does Democrats.