With the House and Senate continuing to mark up their competing transportation spending plans this week, House GOP leaders are looking for the magic formula that will get them the 218 Republican votes needed for passage.

With virtually the entire Democratic Caucus expected to vote against the five-year, $260 billion bill, Speaker John Boehner (Ohio) is leaning heavily on Majority Whip Kevin McCarthy (Calif.) and Chief Deputy Whip Peter Roskam (Ill.) to convince enough Republicans to overcome entrenched opposition among conservatives, and even moderates with district-specific complaints.

They have their work cut out for them. Outside groups such as the Club for Growth already have begun pushing Boehner’s right flank to oppose the bill, and leadership aides acknowledge they could lose as many as 50 conservatives on the final floor vote. Add to that a host of other Members with parochial concerns — ranging from coastal drilling to union restrictions in the bill to the fact that it opens the Arctic National Wildlife Refuge to drilling — and getting to 218 becomes increasingly tricky.

According to lawmakers, McCarthy, Roskam and Transportation and Infrastructure Chairman John Mica (R-Fla.) are hoping an aggressive “education campaign” led by the two Whips, along with the promise of floor votes on Members’ amendments, will bring enough rank-and-file Members and conservatives into the fold to push the measure over the line.

So far, McCarthy and Roskam have held two “listening sessions” — with more planned for today and Thursday — patterned on their budget listening session from last year.

Rep. Bill Shuster (R-Pa.), who has worked closely with Mica and leadership in those sessions, said he believes they are going well so far.

“I feel pretty confident. We’re going through this education process. … We’re moving in the right direction,” Shuster said. Leadership is also likely to use some sort of an open rule process, Boehner announced Tuesday, saying that he hopes for it to “come to the floor in an open process. What that looks like, it’s a little too early to tell, but I think it’s important to continue to open the floor.”

According to Republicans, leaders hope that allowing Members to vote on amendments either on specific issues or broader thematic provisions — most notably conservatives’ demands to devolve the program to states — will ultimately bring Members on board, even though most of those amendments will likely have little chance of passage.

“Leadership wants to accommodate folks,” Mica said Tuesday.

“I think it looks pretty good. … I think we’ll have this done by [Feb. 17],” Mica added.

“I don’t know what the final rule is going to be, but there’s going to be a lot of amendments,” Shuster said.

In some respects, leadership’s efforts appear to be paying off.

Republican Study Committee Chairman Jim Jordan (Ohio) — one of the chamber’s most conservative Members and who has broken with Boehner on a number of high-profile issues — appeared open to supporting the bill.

“I’m undecided but leaning toward it,” Jordan said, adding, “We’re definitely looking at amendments getting this program back where it should be” in the states.

But for others, all the education in the world might not be enough to get them onboard if the bill doesn’t address their specific concerns.

Rep. Steve Southerland (R-Fla.), a member of the Transportation and Infrastructure Committee, said he cannot back the bill unless it addresses his concerns with the offshore drilling provisions, an issue for his heavily coastal district.

Southerland said an amendment further limiting drilling off Florida’s coast “would probably swing my support in favor of the transportation bill.”

But the notion that he might be swayed simply by giving him a floor vote is, according to Southerland, a nonstarter.

“Some people, I find, struggle with distinguishing between activity and productivity. I’m a small-business owner, [and] activity means nothing. It’s got to be productive. So productive would be for an amendment attached to the bill that addresses my concerns. I’m not concerned that we don’t have enough activity around here,” he said.

A GOP leadership aide acknowledged that, in many ways, those with specific issues are the biggest issue.

“This bill is a lot less about ideology and more about parochial issues,” the aide said.

But so far, according to this aide, it appears leadership’s strategy is working.

“People have questions, people have complaints, and yet, when they come into these education sessions and they get their questions answered … they come out in a very different place,” the aide said.

Shuster agreed.

“A lot of it is education. Transportation, for whatever reason, has not been one of those sexy, top-of-the-mind pieces of legislation. But when you come right down to it, it’s the core foundation of our economy,” he said.

Meanwhile, the Senate is proceeding this week with a very different two-year bill that is expected to occupy the Senate’s floor business for some time. “It will go into next week,” Senate Environment and Public Works ranking member James Inhofe (R-Okla.) said, adding that he will have a better sense after seeing the results of the Senate Finance Committee markup, which was still under way at press time.

Senate Finance Chairman Max Baucus (D-Mont.) has proposed transferring revenue from some import tariffs to fully fund the Highway Trust Fund.

“Where we cannot find more revenue from the Highway Trust Fund’s usual funding sources, we have focused on funding that bears a nexus to transportation,” Baucus said in his opening statement.

Senate Finance ranking member Orrin Hatch (R-Utah) has offered amendments to strip Baucus’ offsets and replace them with provisions to expand oil and gas drilling in the Arctic while also fast-tracking the Keystone XL oil pipeline from Canada.