President Barack Obama’s plan to send 30,000 more troops to Afghanistan leaves Congressional Democrats scrambling to support their president as they agonize over the cost of his strategy — and their lack of viable ideas on how to pay for it.

“We didn’t pay for the Vietnam War; we paid a heavy price afterwards. We’re going to do the same thing here if we don’t pay for it,— warned Rep. John Murtha (D-Pa.), chairman of the Appropriations Subcommittee on Defense.

Murtha is one of several influential Democrats pushing a proposal by House Appropriations Chairman David Obey (D-Wis.) to impose a war surtax to pay for military operations in Afghanistan. But even Murtha conceded their idea isn’t likely to gain traction, and he didn’t have a Plan B to speak of.

A war tax “is probably not to be the way it’s done, if anything is done at all,— Murtha said. Pressed on other ways to pay for the war, he said, “The president said he’s going to work with Congress to pay for it. I don’t have any other [proposal] — one is enough for me.—

House Majority Leader Steny Hoyer (D-Md.), a self-described budget hawk, cited the fragile state of the economy in shooting down the prospect of a war tax. And a Senate Republican aide signaled such a proposal would go nowhere in the upper chamber. “I think most Americans would say, ‘I’ll take earmarks or I’ll take stimulus rather than a new tax,’— the aide said. “If I were a moderate Democratic, I’d be running from Obey.—

House Financial Services Chairman Barney Frank (D-Mass.), a supporter of Obey’s bill, said that while Obama has done “as good a job as possible in making a bad case— for maintaining a military presence in Afghanistan, he is still opposed over its costs.

The only way he could endorse the plan is “if we had a proposal to pay for it. I’m stuck on the money issue,— Frank said. “I’m ready to be supportive, but it’s not productive— without paying for it.

“We’re going to have to find a way to fund it,— Rep. Elijah Cummings (D-Md.) said. Asked whether he currently supported Obama’s plan, he said, “I’m trying to get there. I supported the president. I ran his campaign in Maryland. I voted for him. I want him to be successful.—

Democrats’ deep reservations over costs are a sign of the heavy pull in store for Speaker Nancy Pelosi (D-Calif.), whom Obama is counting on to advance funding for his war plan even as she continues to criticize the call for troop increases.

“Yes she is— in a tough spot, Frank said. “She will be lobbying Members to join in opposition, but she also will not use the role of Speaker to obstruct this president.—

Frank predicted that Pelosi would allow a vote on a war spending bill in a nod to Obama but then split apart votes on the bill to “protect a small number of Democrats— who could be hurt if forced to vote on a war supplemental tied to other items that they support.

“She feels very strongly about this,— Murtha said. “She’s a master at working things out. She’s going to give the president every opportunity — she won’t put up roadblocks. But on the other hand, she said nothing [after Obama’s Tuesday address]. Nothing. Everybody knows where she feels.—

Senate Democratic leaders were also noticeably quiet in the aftermath of Obama’s address. Majority Whip Dick Durbin (Ill.) and Democratic Conference Vice Chairman Charles Schumer (N.Y.) have withheld their support as they consider further details of Obama’s plan.

Other key Senate Democrats continue to struggle to find a way to embrace Obama and his costly plan. Senate Armed Services Chairman Carl Levin (D-Mich.) has advocated taxing personal incomes over $250,000, but his proposal is gaining little traction among moderate Democrats.

With or without a viable way of paying for the war, Murtha said to expect the House to take up a $40 billion emergency war supplemental in May or June. That total, which covers the estimated cost of one year in Afghanistan, is $10 billion more than Obama cited in his Tuesday night address. Murtha said his figure reflects the cost of “normal operating expenses— not factored in by the administration.

“Last year, they didn’t even know about the TRICARE shortfall,— Murtha said, referring to health care services for military retirees. “My staff’s more right than they are. I tell them that all the time.—

War costs were hardly discussed in Wednesday’s Senate Armed Services Committee hearing on Afghanistan. Instead, the panel discussed the goal of withdrawing troops in July 2011 with an all-star team of witnesses: Secretary of State Hillary Rodham Clinton, Defense Secretary Robert Gates and Adm. Michael Mullen, chairman of the Joint Chiefs of Staff.

The House Foreign Affairs Committee also spent little time discussing war costs in a hearing with administration officials.

Pelosi and Senate Majority Leader Harry Reid (D-Nev.) were expected to touch on the issue Wednesday in a regularly scheduled leadership meeting focused on moving appropriations bills. But a Senate Democratic aide said those discussions are still at a preliminary stage. “They’re not even there yet,— the aide said.

One thing is certain: Obama will have no luck trying to insert war funds into the fiscal 2010 Defense conference report, which is scheduled for a vote this month. Senate Appropriations Chairman Daniel Inouye (D-Hawaii) and Obey have already declined a request by the White House to do so.

“Anything that’s going to be done is going to be done separately so we can debate it,— Murtha said, indicating that the costs of the war have already exceeded the current budget. “Believe me, there will be a supplemental.—