In the past, both parties have had mixed success in their efforts to covertly, or not so covertly, clear crowded primaries for their best prospects in some of the most competitive House races.

But with the anti-establishment sentiment among voters inflamed this cycle, both local and national GOP leaders are being forced to tiptoe — if they are moving at all — to show some candidates the exit for fear of triggering a backlash from local activists.

About six weeks ago, Missouri state GOP officials attempted to organize a meeting with state Sen. Bill Stouffer and former state Rep. Vicky Hartzler, the leading GOP candidates in the Aug. 3 primary to take on longtime Rep. Ike Skelton (D-Mo.).

According to several sources familiar with the meeting, it was arranged in an effort to talk one of the candidates out of running in order to clear the field. But Hartzler canceled at the last minute.

“Vicki Hartzler canceled the meeting, period,” Stouffer campaign spokesman Christian Morgan said. “She was going to be asked to step aside in the campaign because her support just isn’t there in the district. This isn’t theory. It is fact. Her revisionist history and behavior of toying with the facts is just another reason why she cannot be trusted to represent the people of rural Missouri in the U.S. Congress.”

But according to Hartzler political director Samantha Hill, the story is actually the other way around — party officials attempted to bring the two candidates together to ask Stouffer to step aside in the race. Hill said that when party leaders backed away from their promise to ask Stouffer to step aside just days before the meeting, Hartzler canceled.

“We kind of deliberated, and said it wasn’t worth our time, it wasn’t worth the party’s time and it wasn’t worth Stouffer’s time,” Hill said.

With several notable exceptions, the National Republican Congressional Committee is staying out of the primary game completely. Officially, the committee says it has no policy on primaries — which technically means it reserves the right to take sides even if it is unlikely to do so.

But if the field can be cleared for the right candidate, it will pay off for the national party in November. Given that the NRCC is strapped for cash this cycle, it will have to choose carefully which races it can afford to play in. If many of the candidates emerge from their primaries essentially broke, House Republicans will have major funding problems in some of their most competitive races.

The filing deadline has not passed in several states with late primaries and contested GOP races, and candidates can still remove their names from the ballot in places such as Arizona, Colorado, Connecticut, Kansas, Michigan, New Hampshire, New York and Wisconsin.

Just last week, former Kansas state Sen. Nick Jordan (R) announced that he was dropping out of the primary in the competitive 3rd district open-seat race. Several sources said the 2008 GOP nominee stepped aside on his own volition, but there’s no doubt that if Jordan stayed in the race, a competitive primary against well-funded state Rep. Kevin Yoder would have endangered the GOP’s chances of winning the seat.

Jordan also participated in a Nov. 23 meeting in which top 3rd district GOP candidates tentatively agreed to step aside for the candidate with the best fundraising after the first quarter of 2010.

Jordan — who did not return a request for an interview — raised a paltry $90,000 in the period, while Yoder brought in $277,000.

The November meeting was held in part because GOP primaries have plagued the party’s chances in the competitive 3rd district for several cycles. Two candidates, often a more moderate and a conservative Republican, would run negative races against each other until the August primary, allowing Rep. Dennis Moore (D-Kan.) to continue winning re-election.

“Your Republican nominee would show up the day after the primary, 90 days before the general election, bloody and broke,” Kansas GOP consultant David Kensinger said.

A spokesman for national Republicans argued that primaries will make their candidates stronger in the general election, and that they will have a relationship with every winning primary campaign as a result of their implied neutrality. For example, both Republican candidates in Missouri’s 4th district are in the NRCC’s “Young Guns” program, although Stouffer ranks in the second tier while Hartzler is in the third tier.

“We are not afraid to acknowledge the success of multiple candidates, even if they are running in the same district,” NRCC spokesman Ken Spain said. “Our goal is to make every campaign better.”

Nonetheless, there are less-than-subtle hints about whom the national GOP supports in many of these multicandidate primaries. House Minority Whip Eric Cantor (R-Va.), for example, has endorsed car dealer Scott Rigell (R), the leading contender in the crowded primary to decide who will face Rep. Glenn Nye (D-Va.).

In the race for retiring Rep. John Tanner’s (D-Tenn.) seat, NRCC Chairman Pete Sessions (Texas) and other GOP leaders have held fundraisers for farmer Stephen Fincher (R). Even though Fincher is not the only competitive candidate in the race, GOP leaders have continued to help him because he entered the race and put together a strong campaign against Tanner before the 11-term Democrat announced his retirement.

But by overtly backing a candidate in a contested primary, national and local parties can put themselves in a difficult position if their preferred nominee does not win. The Democratic Congressional Campaign Committee fell into that trap in the 2006 cycle, when its preferred candidate — state Rep. Jim Craig — lost the primary in New Hampshire’s 1st district to now-Rep. Carol Shea-Porter (D).

After Craig’s loss, the DCCC did not target the race and, much to the surprise of Democrats, watched the then-little-known liberal activist defeat then-Rep. Jeb Bradley (R-N.H.) in the general election. Relations between Shea-Porter and the committee remained frosty until fairly late in her first term in Congress.

This cycle in the Granite State, Republicans are faced with crowded primaries in both competitive House districts. National Republicans originally recruited Manchester Mayor Frank Guinta (R) to run against Shea-Porter early on this cycle, but his fledgling campaign has opened the door for many other local Republicans to get in the race.

While NRCC officials have stood by their early recruit in Tennessee, Fincher, they are letting the primary play out for Guinta in New Hampshire. Bradley lost his attempt to take his seat back in 2008 after a late and bloody primary damaged his candidacy and his bank account, but the risk of taking sides in an activist-driven state like New Hampshire is too risky for the national or local Republican Party.

“Being the candidate of the Washington establishment is not quite the kiss of death, it’s certainly not something that any candidate wants to run on this year,” former New Hampshire GOP Chairman Fergus Cullen said.