Two prominent Senate Republicans bucked the White House on Sunday, expressing skepticism about more U.S. troops in Iraq and support for greater dialogue with Iran, Syria and others in the region.

Sen. Richard Lugar, the outgoing chairman of the Senate Foreign Relations Committee, urged the president to consult with lawmakers before announcing a new strategy on Iraq that could call for additional troops in Iraq.

If Bush were to act with without involving the new Democratic-controlled Congress, he can anticipate "a lot of hearings, a lot of study, a lot of criticism," Lugar said.

Bush is expected to deliver his Iraq policy speech — laying out his plan to improve security, assist the Iraqis in reaching a political reconciliation between warring sects and help with reconstruction — before his State of the Union address on Jan. 23.

Sen. Arlen Specter, just back from a trip to the region, also questioned the wisdom of sending in more troops, saying he has not seen an administration plan that would justify it. "If there is a road map to victory, then I would be prepared to listen to what the president has to say about more troops," he said.

The Pennsylvania Republican described the situation in the Mideast as the most serious he has seen in his 26 years in the Senate.

Specter expressed support for the Iraq Study Group's recommendations that the U.S. engage Syria, Iran and others in negotiations on Iraq's future.

Lugar suggested his committee, which Sen. Joe Biden, D-Del., will lead beginning in January, hold a "retreat" to discuss Iraq, even before Bush's expected upcoming address to the nation.

Lugar said the U.S. should not rule out conversations with Iran and Syria, as well as Jordan, Saudi Arabia and Turkey, regarding the instability in the region.

The Indiana senator appeared frustrated that the president has not done more to consult Congress on Iraq policy.

"In the past, the administration has been inclined not to disregard Congress, but to not take Congress very seriously," he said.

When asked whether he would support Bush's plan for a "surge" of more troops into the country, Lugar said "I don't know whether I do or not."

He said the U.S. should have a clear policy on what those troops are required to do. "The administration needs to identify precisely where the battle lines are - who is it we combat. I haven't seen such lines," Lugar said.

Lugar also questioned whether a move to train Iraqis might "lead to Iraqis who are better prepared for civil war against each other."

He said if Bush reaches out to Congress about his plans, hearings before the committee could become "well-informed, sophisticated situations" rather than a "lynching party."

In a partisan flip, Connecticut Sen. Joe Lieberman, the Democrat turned independent, said he supports an expected recommendation by the White House for more troops in Iraq and argued against dialogue with Syria.

When asked if he could support sending another "20,000 to 30,000" troops, Lieberman said, "I can and I hope it's exactly what President Bush does."

Specter recently visited Syria and spoke with President Bashar Assad, despite admonitions from the White House against the trip.

Specter said Assad told him that he was "prepared to work with the United States on tightening the border to impede insurgents" and also that Syria would be willing to host an "international conference" in an attempt to bring peace to the region.

"I respect what the administration is doing, but there are others of us who have been in the region who have studied it intently and have some useful suggestions to make," Specter said.

Lieberman accused Syria of allowing Al Qaeda to cross its borders and kill American troops and of having a hand in recent assassinations in Lebanon.

Meantime, two Democratic presidential hopefuls affirmed their opposition to additional U.S. troops in Iraq.

Iowa Gov. Tom Vilsack said the U.S. should not make a "big mistake even bigger by suggesting a surge of troops in some way, shape or form is going to make Iraq safer or better."

Former North Carolina senator John Edwards, described the troop-increase idea as the "McCain doctrine" — after a chief advocate, Sen. John McCain — and said he believes the Arizona Republican is "dead wrong."

Lugar and Vilsack were on "FOX News Sunday," Edwards appeared on ABC's "This Week" while Lieberman and Specter spoke on a cable news channel.