Had the lady been a Democrat, I suppose it could have been said that her bombshell announcement on Tuesday that she will not seek re-election to a fourth term in the United States Senate had come straight out of left field. But since Maine’s Sen. Olympia Snowe is a moderate Republican, it seems more appropriate to suggest that the surprise she uncorked had come winging in from deepest center field.

Wherever its origin, the declaration that no one had seen coming seems sure to make 2012 a year not soon forgotten in Maine politics. “Snowe’s exit rocks political landscape,” read the banner front-page headline in Thursday morning’s Bangor Daily News. As the fallout settled upon the land, the headline writer had pretty much nailed the situation in five simple words.

If the first response of Mainers to Snowe’s announcement was shock and awe, the second — not far behind — was speculation as to which salivating politicians might leap at the chance to succeed the woman who has represented Maine in the Congress for more than three decades.

The usual suspects in both political parties were not long in staking their claims. Two of the biggest names in the Maine Democratic party — former congressman and two-term Gov. John Baldacci and U.S. Rep. Chellie Pingree of the First District — quickly requested nominating petitions from the Secretary of State’s office, hoping to become their party’s nominee for the job. Second District Rep. Mike Michaud will not seek the vacated Senate seat.

Maine Senate President Kevin Raye and Secretary of State Charlie Summers are among a gaggle of Republicans said to be considering pursuing the GOP nomination. The lone Republican candidate to qualify so far is Scott D’Amboise of Lisbon Falls.

Former independent Gov. Angus King and 2010 independent gubernatorial candidate Eliot Cutler were reported to be considering having a go at it. Others also may have aspirations. Party candidates, who must gather 2,000 signatures to get on their parties’ June primary ballot, face a March 15 filing deadline. Unenrolled candidates have until June 1 to collect the required 4,000 signatures to get on November’s general election ballot.

A common perception is that Snowe’s dramatic decision to retire has given Democrats a good shot at landing what had been considered a safe Republican Senate seat. The national Democratic organization now considers Maine a prime target of opportunity in November. As well, lineups for state and congressional elections have been jostled by the movement at the top of the heap.

Meanwhile, bipartisan accolades have poured in from throughout the country for Snowe, who sits on the prestigious Senate Finance Committee and is respected by both parties for her expertise on many issues. She and her Maine Republican colleague, Sen. Susan Collins, have exerted considerable influence in Washington, often becoming critical swing votes on major issues. In doing so, both have at times infuriated party conservatives, who have disparagingly referred to them as members of the untrustworthy RINO — Republican In Name Only — species.

In one of her re-election campaigns, Snowe plastered the state with simple one-word campaign signs. “Olympia!” the placards fairly shouted to potential voters. Much as was the case with the late, longtime Democratic state Rep. Louis Jalbert of Lewiston — known far and wide simply as “Louis” — one can refer to Snowe most anywhere in Maine simply as “Olympia” (exclamation mark optional) and people will understand the reference. Few other politicians can claim such easy name recognition.

A press conference scheduled for Portland on Friday was expected to clear up the matter of Snowe’s future. In her announcement Tuesday she alluded to the rancorous partisanship that divides Congress, and the opportunity she sees to make a change for the better.

“There are unique opportunities to build support for that change from outside of the United States Senate,’’ she told reporters. “I decided that if I was going to do something different, it had to be at this moment in time. So I am giving my voice to what should change here in the United States Senate and in Congress to get things done for the American people.”

The bottom line is clear: Come next January, Maine will have a new United States senator charged with traveling the path of some notable heavyweights of both political parties. Stalwarts the likes of Margaret Chase Smith, Ed Muskie, George Mitchell, Bill Cohen and Snowe are tough acts to follow. But a history showing that Maine’s sons and daughters elected to the office have routinely excelled is reassuring.

BDN columnist Kent Ward lives in Limestone. His e-mail address is maineolddawg@gmail.com.