A lonely Republican in a state government dominated by Democrats, John Suthers seemed to nonetheless be navigating political life just fine. Then, after President Barack Obama signed the historic and controversial bill reforming the country’s health-care system, Suthers joined a handful of GOP attorneys general from other states in a lawsuit to try to derail the legislation.

Suthers’ move was seen as partisan enough by Boulder County District Attorney Stan Garnett for Garnett to announce that he will seek to replace Suthers in the upcoming election (via the Daily Camera).

“The attorney general, as with any prosecutor, needs to act very carefully on behalf of the interests of the entire state and not any particular faction or group,” Garnett tells The Denver Post, criticizing Suthers for joining the suit, which questions a provision of the new law requiring most Americans to eventually purchase insurance.

Garnett’s announcement isn’t a major surprise: At the end of March, he told Westword he was considering the run, with the paper noting, “the lawsuit alone isn’t enough to convince him to take on Suthers—but he does see it as emblematic of other problematic issues,” including medical marijuana.

Suthers’ reaction to the news has been polite but with a hint of bring-it-on: “I look forward to discussing all the issues that involve the Attorney General’s Office and defending the record of the office over the past five-and-a-half years.”

Colorado Republican Party Chairman Dick Wadhams seems somewhat giddy about Garnett’s entry, telling Longmont’s Daily Times-Call he’d like to see health care become “the defining issue in every race” in Colorado this year: “If that’s the debate the Boulder district attorney wants to have, then let the games begin.” Colorado Democratic Party Chairwoman Pat Waak says she’s received “thousands” of e-mails objecting to Suthers’ lawsuit.