Updated: July 6, 3:40 p.m.

State Senate President Brandon Shaffer (D) will challenge freshman Rep. Cory Gardner (R) next year in Colorado’s 4th district.

Shaffer, an attorney and former Naval officer, announced his plans Monday at a small Fourth of July barbecue with friends and family in Longmont. He will file his candidacy paperwork Tuesday with the Federal Election Commission.

“Our current representative is a politician who has spent much of his career in Washington D.C. as an attorney and Congressman,” Shaffer said in a statement. “Somewhere along the line, he lost his way. Supporting a plan that would end Medicare as we know it was part of a prevailing wind blowing in the wrong direction. Colorado needs a compass in Congress, not a weather vane.”

Shaffer’s candidacy had been expected for some time. He briefly ran for the seat in the 2008 cycle but stepped aside in deference to ex-Rep. Betsy Markey (D), who lost her re-election bid in 2010.

National Republican Congressional Committee spokesman Tyler Houlton issued a statement saying that the Democrat “has led Colorado down a path to economic ruin by championing steep tax hikes, reckless spending, and punitive regulations on small businesses.”

The state’s split-control Legislature was unable to approve a new Congressional map, and the redistricting process is in the courts. The current 4th, which includes the entire eastern border of the state, is strongly Republican even though it switched party control twice. No Congressional candidate has won more than 56 percent of the vote there in the past decade.