AUGUSTA, Maine — As expected, it took less than 24 hours for Maine’s entire political landscape to be turned upside down after the sudden announcement Tuesday from U.S. Sen. Olympia Snowe that she was dropping her bid for a fourth term.

The three biggest names in the Maine Democratic Party all began gathering signatures to run for the U.S. Senate — 2nd District U.S. Rep. Mike Michaud, 1st District U.S. Rep. Chellie Pingree and former two-term Gov. John Baldacci.

No new Republicans took out papers with the Secretary of State’s Office on Wednesday, but Senate President Kevin Raye, now a candidate for Maine’s 2nd Congressional District, and Charlie Summers, the secretary of state himself, are considered the leading GOP candidates.

Raye said late Wednesday afternoon that he had not made up his mind but he was looking closely at the Senate race.

“I’m getting all kinds of advice,” he said in an interview. “There are a lot of discussions happening and I know a number of people are interested in running for the 2nd District should I move over. The situation is certainly very fluid.”

Although not all candidates who take out petitions will necessarily run for those seats, it allows them to keep their options open. Since the filing deadline for party candidates is March 15, time is a factor. Senate candidates must gather 2,000 signatures and House candidates 1,000 signatures by that date.

The movement in the Senate race is expected to affect the two U.S. House races as well and the Secretary of State’s Office confirmed Wednesday that several have taken out papers to run for those seats.

In the 2nd District, Maine House Democratic Leader Emily Cain of Orono and Assistant Senate Majority Leader Debra Plowman, a Hampden Republican, have gotten the paperwork to become candidates, along with Democrat Bruce Bryant of Dixfield, a former state senator.

In the 1st District, Senate Republican leader Jonathan Courtney of Springvale, along with Democrats Sen. Cynthia Dill of Cape Elizabeth and Rep. Jon Hinck, have done the same. Dill is a candidate for the U.S. Senate but said Wednesday that she would consider running for the House instead given the recent circumstances. Hinck indicated he will likely drop out of the Senate race and focus on the House race.

Republican Mark Gartley and Democrats Wellington Lyons, David Costa and David Lemoine, a former state treasurer, and Sen. Phil Bartlett of Gorham also have begun gathering signatures for the 1st District House race.

Four Democrats already had entered the Senate race when Snowe decided against re-election: Dill, Hinck, former Secretary of State Matthew Dunlap of Old Town and Benjamin Pollard, a home builder from Portland. Hinck’s campaign has said he would consider moving to the 1st District race.

Republican Scott D’Amboise of Lisbon Falls is the lone Republican and Republican-turned-independent Andrew Ian Dodge also is in the mix.

On Wednesday, though, all eyes were on the new potential Senate candidates.

A seat that New York Times’ political blogger and analyst Nate Silver estimated had an 85 percent chance of staying Republican with Snowe in the race turned overnight into a 20 to 30 percent chance for the GOP with her gone, he said on Twitter.

Maine Democrats, who haven’t held a Senate seat since 1994, when George Mitchell retired, were eager to seize an opportunity that unexpectedly landed in their lap.

“Maine is now a top pick up opportunity for Senate Democrats. If there is one place in the country that is likely to reject the extreme, anti-middle class, divisive Republican agenda it is Maine,” Democratic Senatorial Campaign Committee Executive Director Guy Cecil said in a statement sent at 5:33 p.m. Tuesday.

U.S. Sen. John Cornyn of Texas, chairman of the National Republican Senatorial Committee, said Snowe’s sudden departure should not change the color of that seat.

“Maine has a proud history of electing independent leaders, including a Republican governor in 2010, and while this will be a key battleground in the fall, I am confident it will remain in Republican hands,” Cornyn said in a statement Tuesday.

Michaud, the Democrat who has represented Maine’s 2nd District in Congress since 2002, was the first to file paperwork Wednesday with the secretary of state, about 18 hours after Snowe, a three-term senator, announced she would not seek re-election.

Pingree followed suit later in the day on Wednesday.

“Running for the Senate isn’t something I had been thinking of,” she said Wednesday. “But this is an incredibly important election for Maine and the country.”

On Tuesday, the Progressive Change Campaign Committee launched an online effort to draft Pingree, Maine’s 1st District representative, into the race. The committee helped encourage Democrat Elizabeth Warren to challenge Republican Scott Brown in Massachusetts.

Baldacci took out papers early Wednesday afternoon as well, the Secretary of State’s Office confirmed. A spokesman for the former governor said he hasn’t made a final decision but is seriously considering his options.

If Pingree or Michaud officially enter the Senate race, their House seats would become open, a possibility that prompted many to begin dipping their toes into those races.

“House and Senate incumbents are very difficult to defeat in any state, so when you have open seats, there will always be a lot of people running for them,” said Jim Melcher, political science professor at the University of Maine at Farmington. “But it’s more complicated in Maine because we’re a state that’s willing to elect independents.”

The two biggest independent names in the state did not rule out getting into the mix. Former two-term Gov. Angus King said in an interview Wednesday that he’s considering a run.

“If I do this, it would be in order to try to do something about the terrible political dynamic in Washington,” he said, echoing Snowe’s reasons for quitting the Senate race.

Eliot Cutler, who lost in a close race for governor to Paul LePage in 2010, also said he has been asked to run.

“I’ve got plenty of time to decide and I’m going to take at least some of it,” he said by telephone.

Independents don’t face the same tight deadline as major party candidates. For an independent to get on the general election ballot, he or she would need to gather 4,000 signatures by June 1.

There was some chatter on Wednesday about extending the deadline for candidates, who now only have until March 15 to gather the required signatures.

Extending the deadline require would legislative approval and House and Senate leaders said that didn’t seem likely.