Rep. Tom Coburn prides himself on being a "real world" lawmaker.
The US House member and physician keeps in touch with his rural Oklahoma district by returning every weekend - to deliver babies.
"Last weekend I delivered four," he says nonchalantly in a soft, Midwestern twang. "It helps me keep perspective."
Determined not to stay long in Washington, the ideologically conservative Dr. Coburn readily bolts from the Republican mainstream when he feels his homespun principles demand it.
In past Congresses, Coburn might have been dismissed as a fringe extremist. But today when he speaks, House Republican leaders can't afford not to listen.
Indeed, Coburn is one of a small but significant number of lawmakers who are wielding unusual influence in the House due to their willingness to break ranks on key issues and upset the Republicans' 223 to 211 majority - the slimmest margin in Congress in more than four decades.
The GOP, as the party in power, is far more vulnerable to such defections, especially from robust factions of conservative and moderate Republicans. For example, Coburn and his fiscally conservative colleagues recently disrupted the House schedule by holding up major spending bills they thought needed cutting.
But Democrats have recently suffered from damaging cracks in party unity too. Most notably, last week conservative pro-gun Democrats joined Republicans to roll back a Democrat-led drive for tighter gun controls.
"In the dynamics of this Congress, those small groups are more important," says Candice Nelson, a Congress expert at American University here.
So potent are the factions led by mavericks such as Coburn that they are throwing into question what style of leadership is currently possible in the House.
House Speaker Dennis Hastert (R) of Illinois has so far failed to communicate a vision broad and grand enough to mobilize disparate groups behind the overarching goal of retaining control of the House in 2000, experts say.
"They have to come up with a big-picture scenario," says Ms. Nelson.
INSTEAD, in recent weeks Mr. Hastert has repeatedly stepped back, dropped any pretense of party discipline, and freed House members to vote as they please on key issues ranging from Kosovo to gun control.
Such a leadership style has drawn criticism as overly laissez faire, and irritated some members who consider themselves loyal team players. But other members say a more free-wheeling House is not only inevitable, it is also desirable.
"The most effective leadership would be to allow the will of the House to work," says Rep. Greg Ganske (R) of Iowa. "Bring these issues to the floor with an open rule [allowing for unrestricted debate and amendments], let democracy work, and in the long run that would be the best thing for both parties."
Mr. Ganske is not a disinterested advocate of unfettered democracy. A staunch Republican moderate from a traditionally Democratic district, he is another of the renegade House members increasingly making their voices heard.
Who are these members, and what is driving them?
Conservative Republicans: House social conservatives and fiscal hawks are gaining increased heft, demonstrated most recently when Coburn spearheaded a campaign last month to rein in spending. Concerned that House leaders were postponing cuts necessary to stay within promised budget caps, Coburn successfully stalled spending bills for agriculture and the legislative branch until they were trimmed down.
The move was instrumental, Coburn says, in pushing Hastert to switch strategies and make broader spending cuts now - rather than await another last-minute budget showdown with the administration like last fall, when Congress lost leverage and gave in to billions in unplanned spending.
"We've gotta find $10 billion [in cuts] to honor our word," says Coburn, poised to delay other appropriations bills that exceed last year's levels. "There's no limitation on what I am willing to do."
Coburn's derailing tactics did not help his popularity among the House GOP, which has given top priority to timely passage of annual spending bills. "I am sure there are people who are sniping and very unhappy with me," says Coburn, who plans to leave Congress after this term. But he defends his actions as an effort to empower - not undercut - House Republican leaders.
"Who is leading the House, the appropriators or the elected speaker?" Coburn asks. "My whole goal is to ... restore the power to the speaker to set the direction, rather than let [a spendthrift] appropriations committee tell our conference what to do."
Moderate Republicans: On the other end of the GOP political spectrum, Republican moderates such as Ganske and Rep. Christopher Shays of Connecticut are enjoying more power because of their willingness to break ranks on key issues, tipping the balance in favor of Democrats.
"I think the leadership has to pay much more close attention to what we are proposing," says Ganske, a plastic surgeon from Des Moines who calls himself a populist.
Ganske has joined a handful of other moderate Republicans in promoting issues - such as the reform of campaign finance and managed health care - backed by Democrats at home and in Congress. Indeed, he is considering using a legislative tactic called a discharge petition next month to try to force a vote on patients' bill-of-rights legislation.
Conservative Democrats: Democrats have also faced setbacks when conservatives from their ranks defect on controversial issues, most recently during last week's gun-control debate.
For example, Rep. John Dingell (D) of Michigan, worked with Republican House leaders to pass a gun-control measure significantly weaker than that endorsed by House Democratic leaders.
Mr. Dingell and 44 other Democrats mostly representing rural districts in the South and West joined with Republicans to pass the amendment 218 to 211.
The final gun bill, however, failed - thanks in part to conservatives from both parties who oppose any gun control.
One of the Democrats who broke ranks, Rep. Gene Green of Texas, says with calls flooding in from pro-gun constituents, his choice was easy. "We all have to get elected from our individual districts. We will be a permanent minority party if we have a litmus test [on gun control]."