Susan Walsh/AP

Crusader Against Government Waste Cuts Senate Career Short

Tom Coburn, R-Okla., is battling a recurrence of cancer.

Sen. Tom Coburn announced Thursday night that he will be resigning his seat at the end of the year as he battles a recurrence of cancer.

"Serving as Oklahoma's senator has been, and continues to be, one of the great privileges and blessings of my life. But, after much prayer and consideration, I have decided that I will leave my Senate seat at the end of this Congress," Coburn wrote in a statement.

"As a citizen, I am now convinced that I can best serve my own children and grandchildren by shifting my focus elsewhere. In the meantime, I look forward to finishing this year strong. I intend to continue our fight for Oklahoma, and will do everything in my power to force the Senate to re-embrace its heritage of debate, deliberation, and consensus as we face our many challenges ahead."

Coburn was first elected to Congress in 1994 as part of a wave of House conservative firebrands swept into office as part of that year's GOP landslide. Like many of his freshman colleagues, he pledged to  serve only three terms. Unlike most of his colleagues, he kept his word.

He returned to Washington as a senator in 2004, handily defeating two prominent Republicans for the nomination and a highly touted Democratic congressman who succeeded him in the House. During the campaign, he portrayed himself as a part-time lawmaker, saying he was willing to put his conservative principles ahead of his party.

In the Senate, he was a crusader against wasteful spending. Before opposition to earmarking became a cause celebre with conservatives, he vowed not to seek earmarks early on in his Senate career. He tried to remove $5.5 billion in what he deemed wasteful projects from the 2009 stimulus bill and was an outspoken critic against the president's health care law.

Coburn, the ranking member on the Homeland Security Committee, also assembles an annual government "Wastebook," a compilation of government expenditures he views as wasteful. The 2013 edition identified $30 billion in program expenditures, including nearly $1 million to "explore the fascinating, often contradictory origins and influences of popular romance as told in novels, films, comics, advice books, songs, and Internet fan fiction."

But Coburn has been an unflinching advocate of his views, even in the face of conservative backlash.

Over the summer, when Sens. Ted Cruz of Texas and Mike Lee of Utah advocated a strategy of defunding Obamacare even if that meant shuttering the government, Coburn criticized the approach as unrealistic and unlikely to succeed. During the early stages of the so-called defund Obamacare debate, Coburn sat, legs crossed, at his Senate desk listening intently to Cruz and Lee as they argued it would be Senate Majority Leader Harry Reid who would shut down the government, not them.

Coburn disagreed emphatically, calling the tactic disingenuous and saying it was doomed to fail. Politically, Coburn's remarks turned out to be prescient, and the shutdown badly bruised Republicans in Congress. Even as the behind-the-scenes Republican squabbling spilled onto center stage, Coburn kept to his small-government principles. He still voted against the continuing resolution that reopened government, arguing against running the government in such a ham-fisted manner.

Last year, he also gained attention for his willingness to negotiate with Democrats on new gun-control measures in the wake of the Sandy Hook Elementary School shooting. But he was unable to reach an agreement with Democrats, and the legislation never passed.

This is not Coburn's first battle with cancer. In 2011, he underwent surgery for prostate cancer and was treated for colon cancer earlier in his career. In his statement, he attributed his resignation to his commitment to serve only two terms.

"I believe it's important to live under the laws I helped write, and even those I fought hard to block," Coburn said.

Coburn's resignation means there will be a special election held next year to fill out the remainder of his term. Republicans are heavily favored to hold onto his seat in a deeply conservative state. Oklahoma is also one of several states that prohibits governors from appointing a placeholder senator, so there will be a vacancy after his resignation until the special election is held.

Coburn missed Thursday's vote on the $1.1 trillion omnibus spending bill. His colleagues praised him for his incorruptible style and voting record.

"TomCoburn: without question one of the most intelligent, principled, and decent men in modern Senate history," said Minority Leader Mitch McConnell's spokesman in a tweet.