Faced with a veto threat from the White House, Republican strategists on Capitol Hill say House and Senate negotiators could potentially forgo a conference report on the transportation bill and instead extend the current authorizations — perhaps into the 109th Congress.

Aides say that prospect represents a doomsday scenario and would be certain to disappoint Members who are expecting funds for projects back home. But the transportation measure is freighted with symbolic significance in this presidential election year, as the president seeks to demonstrate he can hold the line on spending in the face of a massive budget deficit.

“I don’t think we have a conference report if the president plans to veto it,” one senior GOP aide in the House said. “That’s not the preferred option, but it’s there.”

Even after months of struggle and negotiation, the $275 billion highway bill cleared by the House this month came in $19 billion over the $256 billion ceiling set by the White House. Yet the funding level in the House measure is itself miles short of the $318 billion package passed by the Senate.

The final figures in both chambers reflected months of painful choices and cuts. By final passage, the House had already stripped $100 billion in funding from the initial measure envisioned by Transportation and Infrastructure Committee chairman Don Young (R-Alaska).

GOP leaders on Capitol Hill have indicated that they plan to give the White House a prominent seat at the negotiating table. The White House, for its part, has indicated that it could be flexible on its number if the House and Senate stick to key principles — among these, that no money for the bill is drawn from general revenues.

A White House spokesman noted that the House bill is “a lot closer” to what the president has in mind, but refused to speculate on the nature of a compromise.

“I think the press would love for the White House and Congress to negotiate in the press, but we won’t,” White House spokesman Trent Duffy said.

Whatever the case, the current authorizations will have to be extended when they expire on April 30, if no agreement can be reached before then.

President Bush has yet to use his veto pen during his term in the White House, and Speaker Dennis Hastert (R-Ill.) has indicated over the course of the past three years that he has no intention of sending the president legislation that would be rejected.

Bill Hoagland, a top aide to Senate Majority Leader Bill Frist (R-Tenn.), said it is “premature” to be considering alternatives in the event the White House holds firm in its demands.

“I don’t know why we have a legislative branch if we don’t pass bills and conference bills,” Hoagland said. “The White House will be involved in the conference, and we’ll try to get a bill acceptable to the legislative branch and the executive branch.”

Nevertheless, Hoagland added, “I do think anybody who thinks that a bill would be conferenced and sent to the president with a veto threat hanging over it is simply misinformed.”