WASHINGTON — Sen. Olympia Snowe didn’t reach a final decision to not seek re-election until Tuesday, the same day she shocked the political world with the news.

“It was back and forth in my head,” Snowe said in a phone interview Wednesday night. “I didn’t make the final decision until literally (Tuesday).”

The Maine Republican said that after months of whirlwind activity gearing up her campaign apparatus to seek a fourth term, her 65th birthday on Feb. 21 helped trigger the realization that perhaps she didn’t want to spend another six years in a Senate she had come to regard as paralyzed by partisan polarization.

“My birthday last week really focused me on that,” Snowe said. “I didn’t have many moments to reflect at all during this last year and a half when I started working on this whole (re-election) process. I have been going full tilt…Then I started to think about the picture in its entirety in the context of my life.”

Only three or four people knew that she had started to grapple with the idea of retiring after more than three decades spent on Capitol Hill, elected to the House in 1978, and then to the Senate in 1994.

Snowe says she also told a number of other family members about her decision Tuesday ahead of notifying Republican Senate leaders and other lawmakers she is close to — and then making the news public late in the afternoon.

Snowe reiterated Wednesday night that she believed she was on a path to win a GOP primary contest against a conservative tea party-affiliated candidate, Scott D’Amboise of Lisbon Falls, and a general election race against one of four Democrats vying for their party’s nomination. Independent political analysts also rated here a safe re-election bet.

“My motivation was entirely about building the strongest campaign effort, which I did, and working very hard, and it would be in my view a successful one, barring something unforeseen,” Snowe said. “I just had to really think it through and make a very, very tough decision” not to run.

Jonathan Riskind — 791-6280

jriskind@mainetoday.com

Twitter.com/MaineTodayDC