In a bit of pre-election posturing as the race for House majority leaders grinds on, Reps. John Boehner (R-Ohio) and John Shadegg (R-Ariz.) challenged the presumed frontrunner, Rep. Roy Blunt (R-Mo.), to debate them on national television.

Boehner and Shadegg issued a joint release Thursday challenging Blunt to appear with them to "discuss the issues in the race for majority leader."

"It is our understanding Roy has now declined invitations from two nationally-televised Sunday morning news programs to appear with us," read a joint statement issued by the offices of Boehner and Shadegg.

Blunt's office has declined invitations to appear on Fox News Sunday and Meet the Press, a Boehner spokesman wrote in an email.

"It's unfortunate that at a time when House Republicans are having a serious conversation about our future, the candidate who claims to be the frontrunner has so far refused to engage in a debate about how we will reform the House and change the status quo," the joint Boehner-Shadegg statement continued

Over the weekend, Blunt's staff issued a release claiming their boss had locked up the necessary 117 commitments to become the permanent majority leader when members convene for the election on Feb. 2.

Boehner and Shadegg immediately questioned that claim and have continued to try to create a sense of doubt about Blunt's level of commitments among lawmakers and the media. The debate request is a classic campaign strategy for candidates who trail in the race, and frontrunners rarely agree to appear for fear of undermining their level of support.

From the beginning, Blunt has run an under-the-radar campaign, avoiding many of the public appearances and statements made by the two other members. Last Sunday, Blunt chose to appear separately during a series of interviews with Chris Wallace on Fox News.

Responding to the Thursday release, Blunt's staff said he would continue to try to run his race by talking to individual lawmakers behind the scenes.

"Congressman Blunt believes the most serious conversations at this crucial crossroads are best had in private, not in front of TV cameras," wrote spokeswoman Jessica Boulanger in an email responding to the release. "Over 117 of his colleagues like what they hear and are not at all bothered that he has taken his ideas directly to them and not Sunday talk show hosts.

"With every phone call and every meeting Congressman Blunt has with his colleagues, he is engaged in the vigorous debate over the future of our party," Boulanger wrote.

Blunt, who has been the acting majority leader since Rep. Tom DeLay (R-Texas) was forced to resign that post at the end of September, has the built-in advantage of calling on his team of deputy and assistant whips both to support him and help secure commitments from other lawmakers. In contrast, Boehner and Shadegg have tended to use the media more extensively in their campaigns for the No. 2 spot in the House Republican hierarchy. For instance, Boehner announced his candidacy on Fox News. Meanwhile, all three candidates have written editorials in national newspapers.

The debate flap comes as Boehner and Shadegg continue adding to their list of public support.

Rep. Mike Pence (R-Ind.), chairman of the conservative Republican Study Committee (RSC), publicly endorsed Shadegg Thursday after saying he would wait to endorse any candidate until hearing from each of them during the RSC retreat later this month.

Citing that decision in a letter he sent to RSC members Thursday, Pence wrote that "given the addition of a prominent RSC member to the field and given that many members have already expressed a preference, it has become clear to me that an earlier, personal endorsement is now appropriate."

All three candidates have touted their conservative voting records since the race began. Conference conservatives make up the largest single voting bloc, but support from RSC members is divided among all three candidates.

Pence said he chose Shadegg, a former RSC chairman, because he "is a proven conservative leader."

"John Shadegg has demonstrated a passion for the conservative agenda and a heart to build bridges between the diverse members of our Republican conference," Pence said in a release put out by his office.

Boehner used the Pence endorsement as an opportunity to once again cast himself as a reform candidate and challenge Blunt's retention of the majority whip's post.

"If Roy's campaign truly believes he has the race wrapped up, then in the best interest of the Conference he should follow Congressman Shadegg's example, step aside from his post, and allow a full and open race for the whip's position," Boehner said in a release put out by his office.

Pence and Blunt sparred publicly over the House budget bill last spring, escalating an ongoing tension between GOP leaders and a core group of conservative members who are still hoping to overhaul congressional budget rules to reduce federal spending.

In response to the Pence endorsement, Boulanger wrote: "Congressman Blunt remains confident he will win this race and looks forward to the same high-level, productive working relationship with Pence he's always had."

The debate challenge comes as Boehner and Shadegg both upped their announced public support.

Boehner's team released the names of three more public supporters Thursday - Reps. Judy Biggert (Ill.), Richard Pombo (Calif.) and Jean Schmidt (Ohio) - while Shadegg now includes House Judiciary Committee Chairman Jim Sensenbrenner (Wis.), who announced his support Wednesday evening.