Although both Republicans and Democrats had hoped to escape competitive primaries in the open-seat Oklahoma Senate race, it now appears that Republican frontrunner Kirk Humphreys will face at least one well-known GOP challenger from the ideological right as he seeks to succeed retiring Sen. Don Nickles (R).

Still, party insiders argue that the primary will only bolster Humphreys’ stature in the general election against Rep. Brad Carson, the likely Democratic nominee.

Oklahoma Corporation Commissioner Bob Anthony (R) recently filed paperwork with the Federal Election Commission to seek the Senate seat, and he is expected to formally announce his candidacy in February.

Anthony, the longest-serving Republican in statewide office, has been elected three times and enters the race with high name recognition. His family once owned a chain of 300 department stores in 22 states, and in addition to high name identification he also brings some personal resources to the race.

“Bob’s not going to enter a race and not do what’s necessary to win,” cautioned Anthony campaign spokesman Bill Shapard.

Alluding to what is expected to be a campaign theme for Anthony, Shapard said that many conservatives in the state welcomed the primary and maintained that Anthony is the only candidate who has “earned his conservative stripes.”

Anthony is also expected to campaign against the perception that Humphreys, who resigned recently as mayor of Oklahoma City, is the anointed candidate of the state’s Republican insiders.

Humphreys has the backing of much of the state’s GOP establishment, including endorsements from Nickles, Sen. James Inhofe (R-Okla.) and most of the Republicans in the state’s Congressional delegation. Rep. Ernest Istook (R-Okla.), who enjoys broad support among conservatives in the state, had been expected to run for Nickles’ seat, but he decided not to enter the race last fall.

“A primary, as long as it is productive, can be very good for candidates,” Shapard said. “A lot of Republicans in this state feel like that. We want a primary. As Bob has said many times, our opponent is trying to enter this race from the top down and we’re going to enter this race from the bottom up.”

A spokesman for the Humphreys campaign said that they had expected a primary challenge all along, and maintained that the process was good for the party.

“I think it’s all healthy,” said Rick Buchanan. “The more people you get involved the better.”

“With Mr. Anthony getting in the race, it certainly doesn’t change anything that we have planned at all,” Buchanan said. “We’re going to continue to do what we do”

He also brushed aside the notion that Humphreys has essentially been handed the nomination.

“I think if anything the Democrat Party on the national and state level got together to anoint their candidate, but certainly that hasn’t happened here on the Republican side,” Buchanan said.

“King Kirk. Enough said,” countered DSCC spokesman Brad Woodhouse.

Several other Republicans, including state Sen. Mike Fair and wealthy businesswoman Terry Neese, have indicated they are also looking at the race. But Republican insiders acknowledge that the most formidable threat to Humphreys may be former Rep. Tom Coburn (R-Okla.), a physician.

Coburn, who retired from the House in 2000, has given some indication that he is interested in the race and sources indicated that his recently completed treatment and recovery from cancer may have delayed his decision.

A new Web site launched last week, www.draftcoburnforsenate.com, is seeking to build support for Coburn’s candidacy.

“Our goal is to get 50,000 names and we think we can do that in a month,” said David Chapuis, a registered Democrat who set up the site.

Chapuis, who campaigned for Coburn during his 1996 House race, said he did not contact the former Congressman before launching the site, nor has he heard from him since it went online.

The site allows supporters to sign up to support the draft Coburn movement and encourages writing letters to the editor in support of Coburn. The site, which does not mention Humphreys or any other candidate, sings Coburn’s praises for being a “citizen legislator, not another career politician.”

A secretary at Coburn’s family medical practice said the former Congressman was aware of the site but that he had no affiliation with it. Coburn did not return an e-mail seeking comment on Friday.

A spokesman for the National Republican Senatorial Committee shrugged off any negative effects of a competitive primary and reiterated the party’s belief that the GOP will hold the seat regardless.

“Ultimately we know that the Republicans in Oklahoma are going to nominate the strongest candidate and this is a strong Republican state that the president carried by over 20 points in 2000,” said NRSC spokesman Dan Allen. “We feel very confident heading into the final 11 months.”

In the meantime, both parties’ frontrunners are preparing for an all-out battle in November, as recent polling has shown Carson and Humphreys running neck and neck.

Humphreys, who resigned his post as mayor last November in order to run for Senate full time, raised an estimated $550,000 in about 60 days of campaigning and had about $425,000 in cash on hand at the end of the year.

Carson, who is not expected to face a competitive primary, is expected to report $1 million in the bank as of Dec. 31, after transferring $342,000 from his House account.

State Insurance Commissioner Carroll Fisher, attorney Monte Johnson and retired teacher Jim Rogers are the other Democrats looking at the race.