A bloc of Senate Democratic moderates is quietly maneuvering to keep open the option of vetoing two of President Barack Obama’s most ambitious agenda items this year — climate change and health care reform.

Eight Democrats who want to water down new climate change legislation have already joined with Republicans and signed a letter opposing any attempt to use fast-track budget rules to prevent filibusters. Many of the same Democrats also oppose using those budget rules to prevent filibusters of health care legislation.

But without those fast-track rules known as reconciliation, the odds of passing either of Obama’s top two priorities diminishes greatly. Under reconciliation, just 51 votes are needed to pass key budget priorities, rather than the 60 votes usually required under regular order.

Democratic moderates have been couching their opposition to reconciliation with terms like “bipartisanship— and “regular order,— but when pressed, some Senators acknowledged they want to ensure their voices are heard during upcoming debates on global warming and health care.

Senators from energy-producing states like West Virginia and Louisiana are worried new carbon taxes could be slammed down their throats. And fiscal conservatives are concerned they could be left out of the room while liberal Democrats push for a series of tax hikes proposed by Obama.

“My job here is to represent my state, but also in a broader context, reconciliation was not intended as a way to cram down major policy,— said Sen. Mary Landrieu (D-La.), one of the eight Senate moderates to sign the letter opposing reconciliation for climate change legislation. “It was intended for deficit reduction, and it should not be used for other things.—

Landrieu said that if the energy issue is done right, it could unify the country, rather than divide it, but there is a concern that states like hers, which have massive petrochemical industries, could lose out under a cap-and-trade system or a carbon tax.

Sen. Blanche Lincoln (D-Ark.), worries that if only 50 votes plus Vice President Joseph Biden are needed to pass a bill, other Democrats could be shut out of the negotiations.

“That’s absolutely a concern of a lot of people,— she said. “We need everyone in the room. It needs to be done in a bipartisan way.—

But other Democrats said they were concerned that Republicans will filibuster anything Obama pushes on energy and climate change, and the recent run of near-total Republican opposition to Democratic priorities doesn’t give them cause for hope. They argue that reconciliation — and the simple majority it requires — would ensure Democrats can forward their top agenda items.

“I think we should protect it,— Sen. Frank Lautenberg (D-N.J.) said in support of using reconciliation. “Because of this contrary attitude that exists [among Republicans], where whatever we want to do, right or wrong, they just oppose the Democrats,— he added.

Landrieu, however, said Democrats should not assume the worst of Republicans. She argued Democrats should give the other side a chance to come to the table and work toward a bipartisan deal.

“Just because we haven’t had that much luck in the last 85 days, doesn’t mean we’re not going to have much luck in the next 85 days,— she said. “These issues are so big and so complicated that we need to follow regular order in their development. We just simply do.—

The intraparty feud has Senate Democratic leaders looking to fallback positions.

One possibility being kicked around is to include reconciliation rules but saying only that they intend to use them as a last resort, as sort of a club to bring Republicans and waffling Democrats to the table.

“That’s certainly an option,— said Senate Budget Chairman Kent Conrad (D-N.D.), who also continues to float the idea of passing a second budget later this year if needed to bypass filibusters.

Conrad has been caught in the middle of the internecine battle. Conrad maintained his opposition to using reconciliation this year for major legislation, yet he refused to rule it out.

“I personally don’t think it’s a wise course,— he said. “I find that the details of reconciliation have been lost on the people who advance it.—

Republicans have also warned that going the reconciliation route would poison the well for bipartisan negotiations, although they haven’t been squeamish in using the fast-track powers themselves, using the maneuver to push through a series of expensive tax cuts and other legislation when they were in charge.

Sen. Jay Rockefeller (D-W.Va.) didn’t sign the moderates’ letter on reconciliation, but said he’s concerned about the potential for his state to be cast aside if only 51 votes are needed to pass a bill. “I’m always worried that West Virginia is going to be shut out,— he said.

House Democrats, meanwhile, don’t want to give up the chance of being able to avoid the usual Senate gridlock. “It’s a mistake to shut the door on any options,— said Rep. Chris Van Hollen (Md.), chairman of the Democratic Congressional Campaign Committee. “It’s giving away the store before the negotiations begin,— he said.