As the House heads toward a vote on landmark global warming legislation, Democratic leaders are still trying to shore up support from pockets of resistance in their own party.

House leaders are trying to secure a majority for passage in time for a floor vote on Friday. But Agriculture Chairman Collin C. Peterson , D-Minn., who has been working with bill sponsors on specific details, said Thursday the vote could be delayed.

“It might be on Saturday,” he said. “There are still some things that are being worked out.”

“We’ll get there before Saturday, I hope,” said Majority Whip James E. Clyburn , D-S.C.

Earlier this week, it had appeared that the last major holdouts on the bill (HR 2454) came from a bloc of farm belt Democrats, led by Peterson. After reaching a deal Tuesday with the bill’s sponsor, House Energy and Commerce Chairman Henry A. Waxman of California, to grant a series of concessions to rural states, he said he expected most of those members to join him in backing the legislation.

That hasn’t happened. Rep. Earl Pomeroy , D-N.D., a member of the Agriculture Committee and fiscally conservative Blue Dog coalition, said he will vote against the bill.

Despite intense negotiations by the measure’s architects to woo rural and coal states, Pomeroy said his state – which fits both categories – could face a double whammy from legislation that puts a price on fossil fuel emissions.

“I will vote no. My response is to vote the interests of North Dakota. We’re about the fourth most energy-consumptive state in the country,” he said Wednesday evening. On a per capita bases, energy use in Pomeroy’s state is one of the highest in the nation, mostly because of winter heating needs, according to the Energy Information Administration, the statistical arm of the Energy Department.

Pomeroy said he doubted whether the other Agriculture committee members would also go along as easily as expected.

“I expect there will be a lot of those members who still need to carefully consider this,” he said.

Going After New York Votes

Waxman’s lieutenant on the Energy panel, Massachusetts Democrat Edward J. Markey , met Wednesday evening with several of those Agriculture members, in an effort to change their minds.

Markey also met with a bloc of upstate New Yorkers, who remain uncommitted for a variety of reasons, including concerns about how the bill distributes pollution allowances to coal-fired power plants. The key to their support appears to be Rep. Paul Tonko , who chaired the Energy Committee in the New York State Assembly for 15 years and later led a state agency focused on energy efficiency and affordability.