When Tom Coburn leaves the Senate at the end of this year, it may be a while before Washington sees someone like him – because Washington tries its hardest to keep out people like him.

Coburn announced Jan. 16 that due to his struggles with cancer he will resign at the end of 2014 and will not serve the last two years of his six-year term.

The best testament to Coburn’s time in Washington may be the scorn and fear he earned from the Beltway establishment.

Coburn, an obstetrician, came to Washington as part of the famous 1994 Republican revolution. He pledged to serve only three terms, and unlike many of his classmates, he kept that promise. In six years in the House, Coburn managed to upset nearly the entire GOP hierarchy.

Coburn took part in the failed coup attempt against House Speaker Newt Gingrich in the summer of 1997, but he also ended up derailing the coup by declaring that he and the other junior members didn’t want then-Majority Leader Dick Armey to replace Gingrich.

Considering how often Coburn found himself opposing his House GOP elders, especially those on the Appropriations Committee, they were surely happy when he went back to Muskogee to deliver more babies after the 2000 election.

But the heartburn returned for the Republican establishment a few years later when Coburn jumped into the race to replace retiring Republican Sen. Don Nickles.

Among the handful of GOP candidates, the two clear frontrunners were Coburn and Oklahoma City Mayor Kirk Humphreys. If you wanted to see what Beltway Republicans really thought of Coburn, you could have checked out Humphreys’ campaign coffers.

Coburn was arguably the stronger general election candidate, having represented the most Democratic part of the state, which was also the home base of Democratic candidate Brad Carson. But that didn't seem to matter to the men who had served with Coburn or who feared they might have to.

Nickles contributed to Humphreys in the primary, as did Oklahoma's junior senator, Jim Inhofe. Tom Cole was a congressional candidate that year, but he was also the political boss of the Oklahoma GOP, and his campaign contributed to Humphrey in the primary. So did GOP Rep. Wes Watkins of Oklahoma, who had served with Coburn in the House. Coburn’s other Oklahoma colleague in the House, J.C. Watts, endorsed Humphreys.

Meanwhile, the entire Senate leadership also backed Humphreys against Coburn. Majority Leader Bill Frist, Majority Whip Mitch McConnell and Republican Policy Committee Chair Jon Kyl all poured money into Humphreys’ campaign.

Republicans on the Senate Appropriations Committee also were not thrilled about Coburn coming into the upper chamber and crimping their style. Appropriators Kay Bailey Hutchison, Judd Gregg, Richard Shelby and Ted Stevens all gave PAC money to Humphreys. Republicans John Sununu, Gordon Smith and Saxby Chambliss also spent to keep Coburn out.

Lobbyists and corporate PACs put their money behind Humphreys, too – especially those industries that depended on appropriations. Highway contractors and defense contractors backed Humphreys. From Georgetown and McLean, Va., lobbyist checks flew down to Oklahoma – all to boost Coburn’s opponent. Former Texas Senator Phil Gramm, by 2004 a lobbyist for financial giant UBS, also backed Humphreys.

The Washington Republican establishment could not have been more out of step with Oklahoma’s Republican voters, who picked Coburn 61 to 25 percent. (Some of Humphrey’s Beltway backers gave to Coburn in the days before the July primary, when polls showed Coburn the overwhelming favorite.)

This pattern may sound familiar, because it has played out a half dozen times since – in 2010 and 2012, we saw the GOP leadership and K Street lobbyists line up behind Charlie Crist in Florida, Trey Grayson in Kentucky, and David Dewhurst in Texas, while the grassroots backed Marco Rubio, Rand Paul and Ted Cruz.

You could say Coburn was Tea Party before the Tea Party.

And Coburn justified most of the fears of the appropriators and their business clients. Coburn, together with Jim DeMint, waged a long war to ban earmarks, parading out absurd examples such as Alaska's Bridge to Nowhere and Iowa's indoor rainforest. Coburn would embarrass his colleagues by offering amendments to strip out earmarks and use the money for sympathetic causes, such as Hurricane Katrina relief.

Through his six years in the House and nine in the Senate, Coburn has made an effort not to go native. When I interviewed him in 2009, he spoke of “holding the office with an open hand.”

Now, with his health situation altering his priorities and abilities, Coburn is ready to let go of his Senate seat. And even in resigning, he’ll distinguish himself from the typical Beltway creatures:

Coburn’s predecessor now runs an $8-million-a-year lobbying firm, the Nickles Group. The Oklahoma Republicans who came to Congress with him in 1994 – Watts and Steve Largent – still live in Washington, cashing in as lobbyists. Coburn's office promises me he's not going to set up camp in the capital.

The Beltway establishment never wanted Coburn around Washington. Well, the good news for them is that he won't stick around.

Timothy P. Carney, The Washington Examiner's senior political columnist, can be contacted at tcarney@washingtonexaminer.com. His column appears Sunday and Wednesday on washingtonexaminer.com.