Powell said he agreed with the assessment of the Iraq Study Group co-chairmen, Lee Hamilton and James Baker, that the situation in Iraq is "grave and deteriorating," and he also agreed with recently-confirmed Secretary of Defense Robert Gates that the U.S. is not winning the war.
"So if it's grave and deteriorating and we're not winning, we are losing," Powell told Bob Schieffer in an exclusive interview. "We haven't lost. And this is the time, now, to start to put in place the kinds of strategies that will turn this situation around."
President George W. Bush is considering several options for a new strategy in Iraq. The most likely choice would be to send tens of thousands of additional troops for an indefinite period to quickly secure Baghdad.
A 3,500-man brigade from the 82nd Airborne Division, CBS News correspondent David Martin reported on Friday. The troops would be available immediately should the president order a surge into Iraq.
There are about 134,000 U.S. troops in Iraq now.
Powell, also a former Chairman of the Joint Chiefs of Staff, said he did not see the military benefit of flooding Baghdad with American troops.
"I am not persuaded that another surge of troops into Baghdad for the purposes of suppressing this communitarian violence, this civil war, will work," he said, adding that the Iraqi government and security forces must take over.
"It is the D.C. police force that guards Washington, D.C., not the troops that are stationed at Fort Myer," Powell said. "And in Baghdad, you need a police force to do that, and in the other cities, you need a police force to do that, and not the American troops."
Powell also doubted that the U.S. Army and Marine Corps are large enough to support such an operation.
"The current active Army is not large enough and the Marine Corps is not large enough for the kinds of missions they're being asked to perform," Powell said. "We need to let both the Army and the Marine Corps grow in size, in my military judgment."
Asked directly what the U.S. should do in Iraq, Powell said:
"I think that what we should do is to work with the Iraqi government, press them on the political peace, do everything we can to provide equipment, advisers, and whatever the Iraqi armed forces need to become more competent, and to train their leaders so that those leaders realize their responsibility to the government."
Powell, who as a member of the Bush Administration pushed the international community to sanction the invasion of Iraq, said that we are not safer now after nearly four years of fighting.
"I think we are a little less safe, in the sense that we don't have the same force structure available for other problems," Powell said. "I think we have been somewhat constrained in our ability to influence events elsewhere."