The Bush administration is warning Democrats not to pass a short-term war spending bill following an expected veto of a long-term war supplemental later this week, arguing that doing so would wreak havoc with the military’s ability to plan and prosecute the war.

Rob Portman, director of the White House Office of Management and Budget, called the talk among House Democrats — but not their Senate counterparts — of a short-term bill “a major concern” that would tie the hands of Defense Department planners.

Portman noted that much of the spending in the president’s request would fund longer-term contracts for new equipment and repairs.

“They would have to make some very tough decisions because they can’t assume the full year funding is going to be there,” Portman said in an interview last week. “How can you depend on it?”

Democratic appropriators, including Appropriations subcommittee on Defense Chairman John Murtha (D-Pa.) and Rep. Jim Moran (D-Va.), said that when President Bush vetoes the $120 billion-plus war supplemental as expected later this week, they are likely to move a short-term spending bill — similar to a continuing resolution — that would fund the war for about two months.

Democrats are expected to iron out the language for the long-term bill at a conference committee this afternoon, then vote to adopt the conference report in the House Wednesday and in the Senate Thursday.

“This bill means nothing,” Murtha said, noting Bush’s veto threat. “It’s the next bill that matters.” Murtha said it would probably only have a “couple months” of funding in it.

Moran said that having short-term spending bills would keep the pressure on the Bush administration and Republicans to change course in Iraq.

But Portman said, “This doesn’t solve the problem, which is to provide the funding for the troops in an efficient way. It also puts off the inevitable. Are you going to provide the funding for the troops or not?”

Democratic Caucus Chairman Rahm Emanuel (Ill.) countered that the administration has a credibility problem.

“I respect Mr. Portman a great deal, but we know now that there is enough money until June and the White House said we would run out of money in April. The White House is 0-for-1 on honesty.”

Democrats, meanwhile, have not yet settled on a firm plan for the next bill.

Democratic Congressional Campaign Committee Chairman Chris Van Hollen (Md.) denied that the majority intends to hold repeated votes on a series of short-term Iraq spending bills.

“We would like also to begin to address major domestic [items],” Van Hollen said Friday. “Our object is to deal with this responsibly as it comes up. … No one is looking for an opportunity here.”

Even if House Democrats seek to pass a short-term bill, the Senate isn’t yet on board.

“I don’t think that’s the best approach,” Senate Armed Services Chairman Carl Levin (D-Mich) said Friday. “I think it’s too close to the end of the fiscal year for that.”

Senate Democratic aides also downplayed the chances that Senate Majority Leader Harry Reid (D-Nev.) would agree to try to pass short-term funding bills for the war, noting that it likely would tie the Senate floor in knots and prevent Reid from bringing up other Democratic legislative priorities.

“I don’t see it playing out,” said one senior Senate Democratic aide.

Another Senate Democratic aide noted that the Pentagon last week reiterated that they can operate the war with current funds through June and that Congress has “got time to get the president another supplemental bill [following the first veto] and does not need to do stopgap measures.” The aide added that Congress likely would “pass another supplemental pretty quickly after the veto.”

The senior Senate Democratic aide agreed, but noted that much of what Democrats do will be influenced by the public reaction to Bush’s veto and by the level of violence in Iraq.

“Frankly, nobody knows, because it is literally one step at a time,” said the senior aide.

Senate Democratic aides, however, differed on whether their second attempt would include any kind of Iraq language aimed at changing the president’s strategy in Iraq, with one saying a “clean” bill was likely and others saying the language would only be softened.

The senior Senate Democratic aide predicted that the post-veto supplemental measure sent to Bush would have a combination of benchmarks for the U.S. military and for the Iraqi government. That could include a version of the current House language requiring the president to either certify that troops are trained and well-equipped before sending them into battle or publicly state that he is sending troops into combat without full training and/or equipment, the aide said.

Bush would be “hard-pressed to be vetoing that bill,” said the aide.

Democrats in the Senate said they are certainly thinking about their next steps, but that they want to see if the president actually will veto the first bill.

“We will decide where we move from there once we see what decision the president makes. At this point, no decisions have been made as to what’s next,” said Tom Gavin, spokesman for Senate Appropriations Chairman Robert Byrd (D-W.Va.).

Some House liberals, meanwhile, are on board with a short-term Iraq spending bill. Rep. Lynn Woolsey (D-Calif.), co-chairwoman of the Out of Iraq Caucus, voted against the war supplemental but said she would support a two-month funding bill. After that, Woolsey said, she would only support funding to bring the troops home.

“It actually could hold the president more accountable,” Woolsey said of a short-term bill.

Meanwhile, House leadership is confident that they will have enough votes to win passage of the supplemental, likely April 25, despite dropping language that would require the removal of combat troops by the end of August 2008.

Neither Woolsey nor her co-chairwoman, Rep. Maxine Waters (D-Calif.), plan to whip against the compromise bill.

“We’re putting no energy into it,” Woolsey said.

“I don’t see any reason for [whipping against] it,” Waters said. Adding that she does not expect many defections among Democrats who supported the initial bill, she said that she also will not whip in favor of the legislation, despite her role as a Chief Deputy Whip: “They have their votes basically for the bill.”

Van Hollen said he expects the Caucus to vote for the bill that comes out of conference.

“People still see this as an effort to end the war,” he said. “I don’t think people are going to focus that much on the particular wording.”

Levin said it appears the conference report will include some form of binding troop withdrawal — likely a requirement that a draw-down begin within four months — and that the benchmark language will mirror the House version.

And while Levin said Congress ultimately will ensure funding is made available, he said it was important to hold a vote attempting to overturn Bush’s veto.

“We’ve got to have that vote on override to continue the progress towards a change in direction,” Levin said.

Jennifer Yachnin and John Stanton contributed to this report.