Senate Majority Leader Harry Reid (D-Nev.) and Minority Leader Mitch McConnell (R-Ky.) will certainly be held responsible for the success or failure of the health care reform debate, but they’re having increasing difficulty controlling a process that has been commandeered by a bipartisan group of six Senators.

Both leaders have insisted they want a bipartisan health care bill. However, the six-party talks have created friction in Reid’s and McConnell’s respective caucuses — as Republicans bristle that three GOP Senators could give a Democratic health care plan political cover and Democrats fret that their three negotiators are watering down the bill.

The negotiating group doesn’t “understand how their actions are affecting the rest of the Caucus,— said one senior Senate Democratic aide. “They’re in that room for the right reasons, but the political fallout isn’t their main concern.—

Reid in particular has appeared to be employing shifting strategies for how to deal with the talks, which are limited to Senate Finance Chairman Max Baucus (D-Mont.), ranking member Chuck Grassley (R-Iowa), Kent Conrad (D-N.D.), Jeff Bingaman (D-N.M.), Olympia Snowe (R-Maine) and Mike Enzi (R-Wyo.). All sit on Finance.

By getting those negotiators to agree last week to try to reach an accord by Sept. 15, Baucus took some of the pressure off Reid — who has taken considerable heat for setting deadlines that Republicans complained were unrealistic.

But Reid and McConnell’s struggles to drive the process have nearly blown up talks on a couple of occasions. Just last week, Republican Senators inundated Enzi and Grassley with complaints, following news reports that a deal was imminent. That GOP revolt was largely caused by an expectation — set by McConnell — that Republican negotiators will brief the Conference before they sign onto any deal. The anxiety those news reports caused nearly prompted Grassley and Enzi to walk away from the negotiating table.

And two weeks ago, Reid was the one causing tension in the group by urging Baucus to stop entertaining the taxing of health care benefits and start pushing Republicans to accept a public insurance plan. Those directives were interpreted as a demand that Baucus stop negotiating with Republicans.

In both instances, the talks have continued, and aides on both sides of the aisle cautioned that neither Reid nor McConnell have been trying to tell their respective negotiators what to do.

Still, Reid has had several meetings with Baucus in which he has tried to push the Montana Democrat on both the policies being considered and the deadlines Democrats hope to meet.

[IMGCAP(1)]Just last week, Reid pressed Baucus to bring his months-long talks to a close, or face a scenario where the leader might have to bypass him and prepare a bill that could pass using filibuster-proof budget rules, known as reconciliation.

Baucus was able to get more time for negotiations from leadership largely because polls over the past few weeks have shown public support waning for health care reform plans being discussed in Congress, several Democrats said.

“What has happened is that polls show this is less and less popular … so there’s been less and less pressure on Max,— said one Democratic Senator. “There was a lot of pressure, but now it’s backed off.—

Two weeks ago, however, Reid was less focused on timelines and more focused on policy prescriptions that threatened to tear the Democratic Caucus apart. In what one aide described as an “intervention,— Reid tried to get Baucus to abandon plans to tax health care benefits and refocus the bipartisan group on creating a public insurance option and away from the nonprofit cooperative model they were considering.

Despite that intervention, Baucus has still not completely ruled out either taxing some benefits or creating a co-op to compete with private insurance.

The bipartisan group has “hijacked the whole process,— complained one Senate Democratic staffer. “Those six are sort of acting independently from the leadership.—

Several aides said Reid has been doing the best he can at balancing the warring liberals and moderates in his Conference, each of whom have been demanding quick action or a slow-down to the pace.

“He is threading the needle of allowing for as much time as possible for getting a bipartisan solution, while at the same time having backup plans at the ready,— said another senior Democratic aide.

Reid’s willingness to repeatedly revise the timeline for a bill, said yet another senior aide, “shows our commitment to how far we’re willing to go to be bipartisan, because we really want health care reform. It’s not a political exercise.—

Still, senior aides said the deadlines — which have irritated Grassley, Enzi and Snowe — have been helpful in making sure the bipartisan talks progress, rather than languish.

“With [Democrats] somewhat nervous about what lies in store, the leader has been the lead advocate for getting it done right, rather than getting it done quickly,— said one aide. “At the same time, he has focused on making progress so it doesn’t stall.—

While Reid has been trying to tamp down infighting among his own, McConnell has the luxury of a largely united Conference that is overwhelmingly opposed to the health care plans Democrats have been floating — including what they know of what the Finance negotiators are considering.

So McConnell has been pursuing a strategy to push Democrats and the president to the point of political desperation.

“The only way to get Republicans to the table is to get the negotiations into October,— a senior Republican Senate aide said late last week. “Then, Obama will be so desperate he’ll bring Republicans to the table. Right now, he has no motivation to do that.—

Accordingly, McConnell, his leadership team, and the broader Conference are urging the three Republican health care negotiators not to rush the bipartisan talks and to hold out for the best deal they can get.

Reid has charged the Republican leadership with pressuring Grassley and Enzi, in particular, to refrain from making any deal.

But the Republican trio says McConnell is not pressuring them in that way. Republican aides, noting that Grassley, Enzi and Snowe are veteran Senators with a history of working with Democrats, said any attempt to pressure them would be unsuccessful.

Grassley and Enzi brief a majority of the Republican Conference almost every Wednesday afternoon — and have for months — and they brief GOP leaders almost daily.

While Enzi, Grassley and Snowe say they aren’t being urged to resist a deal, neither are they being given carte blanche. GOP aides say they have been reminded they are not negotiating on behalf of the Conference and could find themselves on an “island— if they agree to legislation without first getting it approved.

“They’re not free agents. They’re reporting to us,— McConnell told radio talk show host Hugh Hewitt on Wednesday. “I don’t think they’re going to sign onto a deal that a vast majority of my Conference can’t agree to. And we don’t, so far, like much of anything we see in this big-government, high-tax, mandate approach that the Democratic majority and the president would like to pass.—

Still, Baucus’ decision to reset the deadline race from this Friday to mid-September, is unlikely to sway rank-and-file Republicans. In fact, the GOP’s message of slowing down the process to get it “right— was effective over the past few months.

“The political dynamic I think is the same. I still think that even if [Democrats] get something that one or two Republicans sign off on, they’ve still got a big problem in terms of selling it,— Senate Republican Policy Committee Chairman John Thune (S.D.) said.