Click here to watch "A Good Senator Knows -- Part 1."

Once considered one of the top contests to watch this cycle, the Maine Senate race between Republican incumbent Susan Collins and Democratic challenger Tom Allen is increasingly looking like a safe bet for the GOP. Though polls have narrowed slightly since the spring, Collins has consistently maintained a double-digit advantage.

Still, Collins is being careful not to identify herself with the Republican Party. In the first TV ads to go on air in the contest, she steers clear of mentioning her party ID, focusing instead on what she has accomplished for Maine in her 12-year Senate career.

The Collins campaign released two similar versions of one TV ad, "A Good Senator Knows," late last week. The spots feature Collins speaking to voters about the importance of bipartisanship: "I feel so strongly that Democrats and Republicans have to come together," she says. An announcer then touts her legislative accomplishments, again stressing her willingness to work across the aisle to get things done. One version (subscription) focuses on homeland security initiatives, while the other (subscription) touts Collins' social policy achievements; both stress her opposition to tax breaks for Big Oil.

The Allen campaign has protested the ads as a distortion of Collins' record, particularly on the oil issue. "For Susan Collins to assert that she opposes tax breaks for Big Oil is the height of hypocrisy. She voted for the Bush-Cheney Energy Bill that created the biggest boon to oil companies in American history," Allen's communications director, Carol Andrews, said in a news release. "No matter how hard she tries, she cannot run away from a record of consistently being there for Bush-Cheney on the big issues at the peril of Mainers."

So far, however, the effort to label Collins a Bush Republican does not seem to be working. She is performing well with independent voters and even some Democrats, garnering about one-quarter of the Democratic vote in one July survey.