With Democrats eyeing a White House takeover next year, Congressional leaders may delay major Pentagon spending legislation until a new president takes office in hopes of providing the next commander in chief full funding for a new Iraq strategy.

As a result, a multibillion- dollar emergency war supplemental spending bill now working its way through Congress could be lawmakers’ last opportunity to direct military spending and affect war policy before this fall’s elections. The White House has suggested it would veto any bill that exceeds its request or limits military operations in Iraq and Afghanistan.

“I don’t know if we will get a [Defense appropriations] bill this year,” said Rep. John Murtha (D-Pa.), chairman of the House Appropriations Subcommittee on Defense. “I don’t know if the bill will be signed into law this year, just because of the political situation.”

Not surprisingly, Members are adding money to the emergency supplemental bill for projects not directly related to the Iraq and Afghanistan wars.

Both the House and Senate war spending bills, for example, propose adding up to $3.6 billion for buying 15 additional C-17 cargo aircraft, built by Boeing. In recent years, the Air Force has not sought any funding for more C-17s, but lawmakers have consistently added money for the aircraft to protect jobs in several states, including California.

The final version of the bill is also likely to contain hundreds of millions of dollars in spending for National Guard equipment not requested by the Pentagon. Lawmakers have a history of beefing up spending for the National Guard, a move popular with state and local leaders who rely on the Guard for responding to national disasters and other domestic emergencies.

Moreover, the war spending bill is likely to contain billions of dollars in funding for dozens of small Defense research projects sought by lawmakers. The Senate war bill has proposed spending $1.7 billion on Pentagon research and development, an area of the annual Defense appropriations bill filled with Member earmarks.

Additionally, lawmakers are likely to include a provision in the spending bill barring the Bush administration from spending any new reconstruction dollars in Iraq — unless the Iraqi government matches it. Democrats, who have picked up some Republican support for limiting spending, view the move as a way to change policy in the war without pushing more controversial proposals to pull troops out of Iraq.

Top Defense officials have warned Congress that a final war spending bill is needed by mid-June. Otherwise, the Pentagon would have to scramble to cover those costs from other Defense accounts.

Lawmakers in both chambers are also writing the annual Defense authorization bill, a massive measure that authorizes Pentagon spending — including troop pay raises — and sets a host of military policies. The House and Senate could pass their authorization bills by early summer, but it remains to be seen if a final bill will be sent to the president before November.

Members are using the authorization bill to make the case for changes in Iraq and Afghanistan.

The Senate Armed Services Committee backs a provision in the bill that bars the Pentagon from spending more than $2 million on any Iraq reconstruction projects — regardless of whether Iraqis pay a share of the costs. Armed Services Chairman Carl Levin (D-Mich.) said he’ll propose extending the ban to State Department reconstruction spending when the measure reaches the Senate floor.

House Armed Services Chairman Ike Skelton (D-Mo.) has proposed a provision to the authorization bill that would require the Pentagon to make Afghanistan the military’s top priority, not Iraq.

“We can’t come out unsuccessful” in Afghanistan, Skelton said. “That is the genesis of the attack on the United States. That should be the No. 1 priority, and it worries me that it’s not the No. 1 priority of the administration.”

Adm. Michael Mullen, chairman of the Joint Chiefs of Staff, told Congress this spring that he was “deeply concerned” about deteriorating security conditions in Afghanistan — and predicted even more violence this year than last for troops on the ground as they battle insurgent forces. But he has stopped short of asking lawmakers for more troops for Afghanistan.

Another controversial issue expected to come up during debate over the Defense authorization bill is the Bush administration’s plan for fielding a missile defense system in Eastern Europe. The United States is currently seeking formal agreements to place 10 missile interceptors in Poland and build an associated radar facility in the Czech Republic.

The House Defense authorization bill proposes cutting nearly one-third of the president’s $712 million request for the Eastern European site. Democrats have questioned whether the technology is ready and have been concerned fielding it could harm relations with Russia, which has adamantly opposed the site.

Republicans oppose the cut. Rep. Terry Everett (Ala.), the top Republican on the House Armed Services Subcommittee on Strategic Forces, said, “I believe this sends the wrong message to our allies who have come out strongly in support of the project.”

The Senate bill does not contain that cut, but keeps in place spending limits on the site from previous years until agreements are ratified with Poland and the Czech Republic. Also, the bill would require the new administration to conduct a “full review” of U.S. ballistic missile defense policy and strategy.

Both House and Senate authorization bills also back increasing the basic pay raise for military personnel from 3.5 percent to 3.9 percent — 0.4 percent higher than the president’s request and the current level of private-sector pay raises, as measured by the Employment Cost Index.

There is also mounting support among lawmakers for legislation crafted by Sen. Jim Webb (D-Va.) bolstering veterans’ benefits. The Post-9/11 Veterans Educational Assistance Act (S. 22), circulating in the Senate and House, would expand educational benefits for veterans returning from the wars in Iraq and Afghanistan.

However, the $40 billion to $60 billion price tag over the next 10 years has emerged as a sticking point. Some Democrats have proposed putting it on the emergency war spending bill as a way around pay-as-you-go budget rules.