US:Senator John McCain has defended President George Bush's plan to send more troops to Iraq, warning that withdrawing too early could invite a greater conflagration that would require the United States to return to the region later.
Speaking during a senate armed services committee hearing on the plan, Mr McCain, who is the early favourite to win the Republican presidential nomination in 2008, criticised Democrats who have rejected the troop build-up.
"I believe these individuals . . . have a responsibility to tell us what they believe are the consequences of withdrawal in Iraq. If we walk away from Iraq, we'll be back, possibly in the context of a wider war in the world's most volatile region," he said.
Mr McCain is exceptional, even among Republicans, for the enthusiasm with which he supports the new strategy for Iraq, which would focus US military activity on protecting the civilian population of Baghdad.
Defence secretary Robert Gates told the committee that, although the troop surge could not end sectarian violence in Iraq, it could reduce it sufficiently to allow US forces to start withdrawing later this year.
"If these operations actually work you could begin to see a lightening of the US footprint both in Baghdad and Iraq itself," he said, Mr Gates acknowledged that the plan's success depended on the Iraqi government of Nouri al-Maliki fulfilling its commitments, including providing Iraqi forces and taking steps towards political reconciliation.
"The record of fulfilling their commitments is not an encouraging one. But I will say this. They really do seem to be eager to take control of this security . . . I think that what's perhaps the newest part of this is that it really does put the onus on the Iraqis to come through," he said.
Most senators expressed scepticism about the plan, which committee chairman Carl Levin said was based on the false assumption that there was a military solution to the violence in Iraq.
"The president's most recent plan, like the previous ones, includes no mechanism to hold the Iraqis to their commitments. For America to supply more troops while the Iraqi leaders simply supply more promises is not a recipe for success in Iraq," he said.
Republican senator John Warner, a former chairman of the committee, expressed concern about the prospect of US troops being put in the middle of a civil war.
"I hope your rules of engagement to your forces are such that you do everything you can to avoid American GIs getting caught in a sectarian crossfire," he said.
With polls showing a large majority of Americans opposed to sending more troops, Mr Bush and vice-president Dick Cheney will defend the plan this weekend in television interviews. Support among Republicans in congress is mostly tepid and a growing number of Democrats are threatening to refuse to fund the troop surge.
Democratic representative John Murtha, chairman of a house subcommittee on defence spending, said he will try to block the increase of US forces in Iraq and force the closing of a military prison in Guantánamo Bay by withholding funds.
Mr Murtha, a decorated war veteran with close ties to the armed forces, said his committee will draft a set of conditions to be attached to the emergency spending legislation for military operations that Mr Bush will submit to Congress next month.
"We have a role as elected officials to exert our influence through the power of the purse," Mr Murtha said.
Democrats plan a two-stage assault on the president's plan, starting with non-binding resolutions in both houses of Congress condemning the new strategy and voting some weeks later to block funding.