U.S. Rep. Michele Bachmann's decision to retire uncapped the ambitions of many Sixth District Republicans, and the first to step forward is 2010 gubernatorial candidate Tom Emmer.

"I have never felt more compelled in my life to serve," Emmer said Wednesday to at least 100 supporters at a park in Delano, his hometown. During a brief dry spell in the daylong rain, Emmer ticked off his reasons for running: the IRS' targeting of conservative groups, the Justice Department's search of reporters' records and what he termed out-of-control spending.

"Is this the legacy we want to leave to our children?" he said. "The answer obviously is no, and the time to act is now."

Emmer's return to electoral politics a week after Bachmann said she would not run for re-election brings new energy to a conservative district Republicans had feared they would lose and Democrats had hoped they would snatch. Bachmann's increasingly controversial profile and tumultuous four terms in Congress had put the heavily Republican district at risk, operatives from both parties said.

"Rep. Bachmann would have faced an uphill race" that would have forced the GOP to pump in cash to defend her turf, said former Minnesota congressman Vin Weber, now a lobbyist in Washington, D.C.

Bachmann has been unusually quiet since last week, when she released a pre-dawn video announcing that she would not return to Congress after this term. She then jetted off to Russia on a congressional fact-finding trip. Since her return, she has declined Star Tribune requests for an interview.

With Bachmann no longer a factor, other Republicans are eyeing the rare open seat in a reliable district that takes in Carver and Wright counties, suburban Anoka and St. Cloud.

"No question this should be a Republican district, but we can definitely lose it if we get complacent or nominate the wrong candidate," said Pat Shortridge, who managed two of Republican Mark Kennedy's successful campaigns for the district and is considering running for it himself this year. "You don't win the Sixth just by putting a Republican name on the ballot."

A week after Bachmann's announcement, not a single Democratic has stepped forward. Democrat Jim Graves had pledged to continue his bid despite Bachmann's departure, but soon reversed himself and dropped out.

Minnesota DFL Party Chairman Ken Martin said, "We can win if we have the right candidate, and we can win if they put up the wrong candidate."

He called Emmer "hard-core right-wing" and a failure. He acknowledged, though, that the district would be a heavy lift for Democrats to win and that "a lot of things have to fall into place."

Last year, although Democratic President Obama won Minnesota handily, the district favored Republican candidate Mitt Romney by 15 percentage points.

Emmer has a distinct edge in capturing those voters. He narrowly lost to DFL Gov. Mark Dayton statewide in 2010, but swept up the votes in the Sixth that year. In Wright County, which includes Emmer's Delano home, and Carver County, he had nearly a 2-1 advantage over Dayton. "Tom has a clear advantage," Weber said. "He could well clear the field."

Emmer's entry, along with personal considerations, has forced three Republicans to reconsider their initial interest in the race.

Former state Senate Majority Leader Amy Koch has decided not to compete for the seat. Instead, she said: "I am endorsing my friend and fellow Wright County neighbor Tom Emmer for Congress."

State Rep. Peggy Scott and Sen. Michelle Benson have also backed away.

But Emmer doesn't have a clear shot to November 2014. Republicans worry that his loss to Dayton in a banner GOP year was a bad sign and that his job the past two years as a talk-radio host will provide fodder for attack.

Meanwhile, Shortridge and four other Republicans are possible contenders. State Sen. John Pederson, of St. Cloud, has said he's seriously considering a run, while Rep. Matt Dean of Dellwood remains undecided.

And even as Emmer was making his intentions official, Republican mega donor Harold Hamilton, founder of Micro Control, was declaring his support for another potential candidate. Hamilton wrote on Facebook that his favorite is Anoka County Commissioner Rhonda Sivarajah. "We need a candidate who can reach out beyond the base to help the GOP ticket up and down the ballot," he wrote. "I hope you will join me in encouraging Rhonda to run for Congress."

Rachel E. Stassen-Berger • Twitter: @RachelSB