Republican presidential candidate, Sen. John McCain, R-Ariz., addresses the 87th annual convention of the Disabled American Veterans on Saturday in Las Vegas.

Las Vegas ? Republican John McCain on Saturday issued a scathing critique of Barack Obama’s judgment and readiness to be commander in chief, telling a veterans’ group his Democratic rival had tried to “legislate failure” in Iraq and placed his own ambition ahead of military success there.

Addressing the Disabled American Veterans convention here, McCain mocked what he called Obama’s varying positions on the Bush administration’s decision to send an additional 30,000 troops to Iraq last year. The GOP candidate supported the so-called “surge” strategy, even as polls showed most voters opposed sending more troops into combat at the time.

Obama spoke out against the original invasion as an Illinois state senator and strongly opposed the subsequent troop increase in the U.S. Senate and on the campaign trail.

Since then, the surge has been credited with helping stabilize Iraq and reduce violence there. Obama has argued that it has not brought about the political reconciliation between rival Sunni and Shia factions needed to create lasting peace in the country.

But in a tacit acknowledgment that his original assessment of the troop increase may have proven incorrect, Obama’s campaign removed criticisms of the strategy from its Web site last month.

Narrowly trailing Obama in national and many battleground state polls, McCain, a 71-year-old decorated Navy veteran and member of the Senate Armed Services committee, has increasingly tried to portray the 47-year-old Obama as lacking the experience and judgment to lead the country in a dangerous world.

Obama, in turn, has criticized McCain for supporting the original Iraq invasion which polls show many voters now consider a mistake. Recently, Obama, who has made Afghanistan a centerpiece of his anti-terrorism strategy, has said the protracted Iraq conflict has drawn needed resources away from Afghanistan where al-Qaida and Taliban forces have shown a resurgence.

“Senator McCain continues to be stubbornly committed to the Bush administration position of an indefinite military presence in Iraq, despite the fact that the Iraqi government is calling for a timeline, despite the fact that the Iraqis are sitting on tens of billions in oil surplus while our economy is struggling at home, despite the impact on our troops and despite the deteriorating situation in Afghanistan,” Obama spokesman Hari Sevugan said.

In his speech, McCain said Obama had not only predicted the troop increase would not succeed but had taken steps to ensure its failure, saying Obama had tried to prevent needed funding for it.

“Not content to merely predict failure in Iraq, my opponent tried to legislate failure,” McCain said.

Obama voted against one major military appropriations bill in May 2007, but otherwise has voted consistently for funding to support the war.

McCain also renewed his criticism of Obama’s call for a timeline to remove troops from Iraq, even as the U.S. and Iraq are near an agreement to pull American combat troops from the country by October 2010.

McCain later told The Associated Press that he believed the agreement being negotiated was not a timeline, as advocated by Obama.

“It will be notional and aspirational dates, but it will be based on conditions, I know that,” McCain said. “They will be times that we hope they can be out by. They will be based on conditions on the ground, not according to hard deadlines.”