Rep. John Kline's announcement Thursday that he would not seek re-election set off early scrambling by potential candidates in both parties for what will be a competitive open seat in the changing Second Congressional District south of St. Paul.

Although President Obama won the district in 2012, Kline, a Lakeville Republican, won his seventh term easily in 2014. With Kline out, a host of Republicans could join two well-funded DFL challengers plus others who may want to jump in now that the incumbent is leaving.

When asked why he was stepping down, Kline, 67, said, "It's time." He also pointed out that in the next Congress, he was scheduled to lose his powerful perch as chairman of the House Education and the Workforce Committee because of term limits on chairs.

In a 30-minute conference call with reporters, Kline said, "Never say never," when asked about a potential run for governor or the U.S. Senate. But he said more fishing and golf would be an early order of business upon returning to Minnesota full time.

With 16 months left in his term, Kline said he still has big plans, including an overhaul of the No Child Left Behind law that he is shepherding as chairman of a conference committee ironing out differences between House and Senate versions.

Kline will end 14 years in elective office following a distinguished career in the U.S. Marine Corps that began in 1969. During his time in the military, Kline went on to fly the presidential helicopter Marine One, served as a military aide to Presidents Carter and Reagan, and carried the launch codes often referred to as the nuclear football.

On his third try running for the House in 2002, Kline ran and won as a conservative Republican and maintained a conservative voting record. He cited Reagan in his statement announcing his decision not to run: "[Reagan's] vision of America as a 'shining city on the hill' has guided my decisions throughout my tenure in Congress," he said, referring to the 40th president's use of the John Winthrop maxim.

Kline, who is on the House Armed Services Committee, has focused on defense and veterans' issues, but he has wielded the most influence and received the most attention — including some critical — on education, labor and workforce policies.

His education bill, the most significant federal K-12 education legislation in more than a decade, would scale back the role of the federal government in schools and allow federal dollars for poor students to follow them to whatever school they attend, which House Democrats argue would hurt poor schools and school districts. The Senate version is a compromise bill that also would shift power back to the states but that was more amenable to Democrats, passing with 81 votes. Kline must now help craft a deal and get it signed by Obama even as the White House promised a veto over provisions of the House bill.

Separately, Kline helped cut a deal with the Obama administration to keep student loan rates low in recent years, but he also has faced criticism for his legislative support of for-profit universities — a major campaign contributor — even as the schools faced increasing scrutiny from regulators connected to allegations that they were taking advantage of students.

In a White House statement Thursday, Obama praised Kline's record of service. "John's never been afraid to stand up for what he believes in, and as the Chairman of the House Education Committee, he's shown a willingness to work together with anybody — Republican or Democrat — who has the best interests of our students at heart."

Kline acknowledged that without the advantage of his incumbency, the Second District is a swing district. Republicans' ability to hold the district, he said, would turn on the candidate. He declined to endorse a successor, but said he expects to support the nominee. Within hours of his announcement, national political handicappers had begun moving his seat from "safe" to "tossup."

Democrats are already more hopeful about their 2016 chances given the makeup of the district and two early recruits: Mary Lawrence, a doctor, and Angie Craig, a St. Jude Medical executive. The United Steelworkers union on Thursday afternoon announced its early endorsement of Craig.

Rep. Joe Atkins, DFL-Inver Grove Heights, said he would make an announcement about his intentions next week; he released a statement thanking Kline for his service, as did Lawrence and Craig. Rep. Rick Hansen, DFL-South St. Paul, is another potential candidate.

Sen. Dave Thompson, R-Lakeville, is seen as a serious contender on the Republican side. Others mentioned include Reps. Steve Drazkowski, R-Mazeppa, and Tony Albright, R-Prior Lake; Dakota County Commissioner Mary Liz Holberg; Sen. Eric Pratt, R-Prior Lake; and David Gerson, a Tea Party favorite who twice ran against Kline as being insufficiently conservative.

Staff writer Jim Spencer contributed to this report. Patrick Coolican • 651-925-5042