Two days later, he shut it.
Sen. Norm Coleman, a Republican from Minnesota, returned from two days in Iraq and stated his opposition to a troop surge.
"It would create more targets," he said.
As President Bush considers whether to boost the number of U.S. troops in Iraq temporarily, few members of Congress are stepping forward forcefully to promote the idea.
The bulk of the political response ranges from silence to skepticism to outright opposition.
Bush is considering whether to add as many as 30,000 troops to the force of about 140,000 already in Iraq, but he has not committed to the idea.
The president is expected to launch a new Iraq strategy, which he calls a "new way forward," in early January - just as Democrats are moving into majority positions in the House and Senate after a midterm election widely interpreted as rejecting the president's conduct of the Iraq war.
Members of Congress have limited reach in shaping day-to-day policy in Iraq.
The impact of their votes on spending for the war will play out only in months and years to come, and the president has demonstrated time and time again his readiness to buck the tide of Democrats' opposition.
But broad political opposition has historically put reins on unpopular military policies. Some members of Congress are asking what mission the troops would be charged with performing, and are questioning the likelihood of success.
Republican Sen. John McCain of Arizona, considered a front-runner for his party's presidential nomination in 2008, has been a leader of a limited group that has pressed for a more aggressive approach in Iraq, including the dispatch of more troops to stem the sectarian violence and insurgent attacks.
Sen. Joseph I. Lieberman of Connecticut, the Democrats' 2000 vice presidential candidate who won re-election to the Senate in November as an independent, has strongly favored sending additional troops.
McCain, Lieberman and Sen. Susan Collins, a Maine Republican, visited Baghdad last week.
Collins said she was "not yet convinced that additional troops" would help bring a lasting peace.
Their comments aside, many Republican leaders have been reluctant to express themselves on the question, and Democrats who have spoken about it remain skeptical or oppose a troop increase.
The incoming Senate Republican leader, Sen. Mitch McConnell of Kentucky, has made no public statements on whether to increase the deployment.
He is waiting "to hear from the folks at the Pentagon," said a spokesman, Don Stewart.
On Sunday, Reid said on ABC News' This Week that he would go along with a troop surge if it lasted two or three months and was "part of a program to get us out of there ... by this time next year."
But two days later, he came out against an increase.
In a blog posting on the Web site Huffingtonpost.com, he wrote: "Frankly, I don't believe that more troops is the answer for Iraq. ... I do not support an escalation of the conflict."
James Gerstenzang writes for the Los Angeles Times.