Email HELENA – U.S. Rep. Denny Rehberg is telling fellow Republicans at a Saturday night GOP event featuring tea party favorite Minnesota Rep. Michele Bachmann that he is challenging U.S. Sen. Jon Tester in the 2012 election — as many of them had hoped.Rehberg’s decision means he will leave behind the easy re-election wins he’s enjoyed to the state’s sole congressional seat to create the biggest Montana political matchup in years. Both parties expect a multi-million dollar slugfest that is sure to be one of the marquee Senate races of 2012.Rehberg has already been drawing philosophical differences by blasting the policies of the Obama administration that Tester has often supported. Rehberg contends the economic stimulus bill has been ineffective and he has bashed the federal health care law as misguided.The Republican has appeared far more comfortable attacking Democratic policies as he travels the state and holds town meetings, than he had been defending those of President George W. Bush. After easily fending off a tea party primary challenge last year, Rehberg has cozied up to the movement as he criticizes federal deficit spending.Tester’s office criticizes Rehberg for opposing their bipartisan plan to rescue the timber industry in a deal that would have mandated more logging while also increasing wilderness area elsewhere. Tester, who has made advocacy of veterans’ affairs a prime issue, has also criticized Rehberg for announcing his candidacy at an event with Bachmann after she advocated less spending on veterans.“When Montanans choose their candidate a year and a half from now, we look forward to an honest debate, comparing Jon’s record as a hardworking farmer against anyone else’s,” said Tester spokesman Aaron Murphy. “Until then, we hope Congressman Rehberg does a better job explaining his support for stripping benefits from Montana’s veterans.”Both sides, in the months leading up to the anticipated matchup, have also been very public about drawing a distinction on congressional earmarks, which Rehberg once supported to boost federal projects in the state.But he has become a critic in the debate that has identified them as a symbol of the nation’s overspending.Tester, who bashed them as secretive while running in 2006, now says they are needed so that spending authority doesn’t rest entirely with the president. Tester argues a new process ensures the earmarks are vetted publicly.Democrats have controlled both of Montana’s U.S. Senate seats since Tester beat Republican Conrad Burns in 2006 — a man that Rehberg helped elect in 1998 by running a campaign that was effective in bashing wilderness plans at the time.Rehberg, 55, worked a variety of jobs — from gymnastics instructor to real estate sales — before getting into politics. He holds a political science and administration degree from Washington State University. He worked as a staff member for former U.S. Rep. Ron Marlenee before winning election to the state Legislature in the 1980s. He was appointed lieutenant governor under Stan Stephens and then elected to that post on a ticket with Marc Racicot.The race against Tester will be Rehberg’s second run for U.S. Senate after losing a bitter election battle with U.S. Sen. Max Baucus in 1996. He first won Montana’s sole congressional seat in 2000.Tester, 54, never strayed far from his family’s Big Sandy farm before 2006, when he delivered a stunning feat against Burns. Tester holds a music degree from the University of Great Falls and served on the local school board before joining the state legislature in 1999. Stay Connected with the Daily Roundup. Sign up for our newsletter and get the best of the Beacon delivered every day to your inbox.