About 200 lawmakers were invited to the Pentagon for a classified question-and-answer session on Thursday with General David Petraeus, the top U.S. commander in Iraq, and Ryan Crocker, the U.S. ambassador there. Bush's new war adviser, Lt. Gen. Douglas Lute, also was to be in the room.Later in the day, Crocker was scheduled to testify publicly before the Senate Foreign Relations Committee, also by video link.The officials were expected to make the case that some progress has been made in Iraq since Bush ordered the deployment of some 30,000 extra troops earlier this year. The officials also were expected to argue it is too early to tell whether the strategy is working, and that members of Congress should hold off on demanding change until at least September.The briefings cap off a week of contentious Senate debate on the war and a public relations blitz by the administration to shore up GOP support. Republican support is crucial for Bush because of the narrow margins in the Senate and the minority party's ability to block any legislation with a filibuster.So far, GOP lawmakers have been mostly united in rejecting Democratic demands to set a deadline for troop withdrawals. On Wednesday, they helped scuttle a bill by Sens. Carl Levin, D-Mich., and Jack Reed, D-R.I., that would have ordered troops to start leaving this fall and end major combat by April 30.The legislation was backed by a slim majority of senators in a 52-47 vote, but fell short of the 60 votes needed to cut off debate and end a GOP-threatened filibuster.On Wednesday as senators cast their vote, Secretary of State Condoleezza Rice shuttled between meetings with members on Capitol Hill to make the administration's case for the war. Bush's national security adviser, Stephen Hadley, has made similar rounds, including a private briefing on Iraq last week for more than a dozen GOP senators.Members say they are happy about the administration's new outreach effort, even if they disagree with the message or still have doubts about the war. Still, it was unclear how many members were planning to take up the White House on its offer to be bused to the Pentagon.Reps. Ike Skelton, D-Mo., chairman of the House Armed Services Committee, and Duncan Hunter, R-Calif., the panel's ranking Republican, planned to go. Sens. John Warner, R-Va., Susan Collins, R-Maine, and Charles Schumer, D-N.Y., also were expected to attend.