Rep. Marilyn Musgrave’s (R-Colo.) re-election appears to be in peril a little more than two months before Election Day, according to a new poll conducted exclusively for Roll Call.

The survey also found the presidential contest between presumptive Democratic nominee Sen. Barack Obama (Ill.) and presumptive GOP nominee Sen. John McCain (Ariz.) was essentially tied in Musgrave’s eastern Colorado 4th district — territory that has historically been a Republican bastion.

Democrats descended on Denver this week for their nominating convention as a way of signaling their commitment to making the Centennial State — and the Mountain West as a whole — competitive in the presidential race. The poll done for Roll Call seemed to bear that out, as McCain led Obama by just 2 points, 48 percent to 46 percent.

Meanwhile, Musgrave trailed Democratic challenger Betsy Markey 50 percent to 43 percent in the poll conducted by SurveyUSA for Roll Call. Seven percent remained undecided. In an equally troubling sign for Musgrave, 51 percent of respondents said they had an unfavorable view of the three-term Congresswoman, while 31 percent viewed her favorably.

The poll of 618 likely voters was taken Aug. 22-24. It had a 4-point margin of error.

The survey found that Markey had a big lead among female voters, 53 percent to 38 percent. The two women were essentially tied among male voters.

More importantly, Markey had a huge lead in two voter groups that will be essential in deciding the election: independents and moderates. She led by 30 points among independent voters, 59 percent to 29 percent, and by 41 points among self-described moderates, 67 percent to 26 percent. Musgrave will have to close the gap in those two groups in order to have a chance at making the race competitive heading into Election Day.

Musgrave has faced difficult races since winning an open-seat contest in 2002 with just 51 percent of the vote. Last cycle, she was targeted by Democrats and won a second term with only 46 percent of the vote, the lowest winning percentage of anyone elected to the House in 2006. Democratic nominee state Rep. Angie Paccione, who was viewed by some as too liberal to represent the largely rural district, garnered 43 percent of the vote and Reform Party candidate Eric Eidsness got 11 percent.

National Democrats are targeting Musgrave again in 2008 and the Democratic Congressional Campaign Committee has already reserved $667,000 worth of TV advertising — which represents a significant buy in the district — according to documentation obtained by Roll Call.

Cash-strapped national Republicans also plan to invest significantly in the contest, with their independent expenditure arm reserving more than $1 million in TV time.

In Markey, a politically moderate businesswoman who is a former aide to Sen. Ken Salazar (D-Colo.), Democrats believe they have found a candidate who can win the district.

While Musgrave has consistently underperformed the underlying nature of a district that has been represented in Congress by a Republican for 35 years, the poll’s presidential findings reflect a troubling shift for the GOP.

President Bush won 58 percent of the vote in the 4th district in 2004, 1 point better than his 2000 performance.

Obama led among women 49 percent to 44 percent in the poll, while McCain had a 10-point lead among men, 52 percent to 42 percent. Obama and McCain were viewed favorably by roughly the same percentage of voters, but Obama had a higher unfavorable rating, 43 percent to McCain’s 35 percent.

Mirroring national polls, the survey found that the economy was by far the biggest issue on the minds of voters, as 41 percent of respondents said Congress should focus on that issue above all others. Immigration was second with 11 percent of respondents saying that is the most pressing issue. All other issues, including Iraq, terrorism, gasoline prices and the environment, polled in the single digits.

The survey found that voters overwhelmingly blame oil companies for the high price of gas. Thirty-eight percent of respondents blamed oil companies, whom Democrats have been seeking to link to Republicans in paid media advertising. Congress and environmentalists were tied for second in blame for gas prices, with 14 percent.