Speaker John Boehner today will make the case to Republicans that a transportation spending measure being worked on in the House is not only a radical departure from past bills but fits squarely within conservative ideology.

The Ohio Republican could have his work cut out for him: Conservatives in his Conference feel they were shut out of developing the bill and worry they will be forced into voting for a measure that they don’t support and that has little chance of passing the Senate.

“Conservatives are being put in a bad position by their leadership, just as moderate Democrats were by their leadership” when then-Speaker Nancy Pelosi (Calif.) pushed a climate change bill that included a cap-and-trade system for emissions, one activist warned. That bill died in the Senate but became a rallying cry against Democrats in the 2010 elections.

Backers of the transit measure dismiss those concerns, arguing that Boehner and Transportation and Infrastructure Chairman John Mica (R-Fla.) have crafted the legislation to address those issues.

According to leadership aides, Boehner will make the strongest case to date for the highway bill, which melds infrastructure spending and revenues from energy development in what Republicans believe will be a political weapon against Democrats.

Boehner will tell his colleagues that “this is a new and different animal and not like highway bills in the past,” one GOP aide said, explaining that the House’s top Republican hopes to nip growing complaints from conservatives in the bud.

Although Boehner and some of his more conservative Members have been at odds during the past year, the fact that Boehner has never voted for a highway bill could help him make his case, aides added.

House Majority Whip Kevin McCarthy (R-Calif.) has been quietly working the Conference on the bill — even though committees are just this week beginning consideration. Leadership aides said McCarthy has begun discussions with a number of conservatives on the bill.

The leadership push is part of an effort to build momentum for the five-year $260 billion bill orchestrated by Boehner with a goal of bringing the package to the floor before the end of February.

Transportation and Infrastructure Committee Republicans — who will mark up the bill Thursday, just two days after it was unveiled — touted the bill’s reforms to the highway spending program.

“This is probably the most important piece of legislation the Congress will consider to put people to work and also cut some of our reliance on foreign energy,” Mica said at a news conference, pointing to the elimination or consolidation of some 70 federal programs as a key aspect of the bill.

Rep. Bill Shuster (R-Pa.) argued that “we are going to reduce the size of government” while still helping build new infrastructure, which he called a GOP tradition.

Privately, Republicans also said they see the bill as a politically strong tool, noting that highway spending and domestic energy production are issues that poll well, and if Senate Democrats or the White House stand in the way of the bill, it could become a defining issue in the 2012 elections.

Nevertheless, conservatives Tuesday said they are skeptical.

“Highway spending has gotten totally out of control” and has become a symbol for the problems with government, Heritage Action for America CEO Michael Needham said.

Needham argued that while Boehner is reforming federal programs and making a strong play to open up areas like the Arctic National Wildlife Refuge to drilling, Republicans need to reduce overall federal spending.

“This is not a jobs program. Republicans shouldn’t be in the business of calling a highway bill a jobs program,” he said. He added that saying increased federal spending is OK if it’s paid for is “not the right message to be sending … to grass-roots activists.”

Democrats and their allies echoed the conservatives’ concerns.

Rep. Jerrold Nadler (D-N.Y.) said in a statement that he is “disturbed by the un-democratic and non-transparent fashion with which the majority has drafted and introduced its bill. Democrats have been left entirely out of the process and, now, after more than a year of waiting for this legislation, we have 48 hours to assimilate 800 pages before it is marked up.

“This is certainly not an inclusive and open process that encourages — or enables — bipartisan feedback. And we surely don’t have sufficient time to fully understand the implications of the policies being proposed,” Nadler said.

House Minority Whip Steny Hoyer (Md.) dismissed the legislation as a political stunt, saying, “We ought to stop playing pretend.”

David Goldston, director of government affairs for the Natural Resources Defense Council, agreed, saying that the bill will “actually block any actual jobs or action on transportation.”

“Instead of legislating seriously, what the Republicans are about to put out is an inventory of all the worst ideas they’ve had for the last two decades. There’s no reason for this to happen” because the Senate is unlikely to take up the bill this year, Goldston said.