Sen. Olympia Snowe, right, bucked her party to kill the so-called Blunt amendment. But her Maine colleague, Sen. Susan Collins, left, voted to support it.

Just days after announcing her retirement due to the partisanship of the Senate, Republican Sen. Olympia Snowe helped kill a conservative measure which would have restricted the availability of contraception. Her Maine colleague, referred to as Snowe’s moderate “sister,” voted to support the bill, however.

Snowe became the lone Republican Thursday to vote against Sen. Roy Blunt (R-Mo.)’s amendment, which would have exempted nearly all employers from President Obama’s new rule mandating coverage of birth control for women. The amendment failed in a close 51-48 vote.

Snowe stunned the political world just two days earlier by revealing that she would not run for re-election this year, by saying, “Unfortunately, I do not realistically expect the partisanship of recent years in the Senate to change over the short term.”

She had become of the rare GOP moderates in the Senate.

Snowe on Wednesday called the Blunt amendment “much broader than I could support,” giving voice to the kind of political independence which has become a hallmark of her 33 years of service in Congress.

However, Snowe’s home-state colleague and fellow Republican moderate, Sen. Susan Collins, chose to support the attempt to restrict birth control.

That Snowe and Collins had chosen a more-moderate course gave the pair “outsized influence in the Senate in recent years as they frequently became crucial swing votes on major issues,” according to a Maine newspaper.

But while the departing Snowe decided, once again, to walk away from the GOP party line, Collins, up for re-election in 2014, chose to hew to it.

Speaking on the Senate floor ahead of the vote, Collins says she was conflicted about the Blunt amendment but complained that those in the Obama administration “are playing politics with” the birth-control issue.

“… I feel I have no choice. I hope the amendment will be refined, and I also hope that the senate will move forward to address the many important pressing issues facing our nation and stop engaging in what is clearly an election year ploy,” she says.

Meanwhile, she had to look only to her soon-to-be-departed fellow senator from Maine to see that a choice was indeed possible.

Scott Nance is the editor and publisher of the news site The Washington Current. He has covered Congress and the federal government for more than a decade.