Members of the U.S. Army's 2nd Brigade, 82nd Airborne Division patrol an area in central Baghdad in this Feb. 17, 2007, file photo.

Baghdad ? A year ago in Baghdad: Shiite militiamen and Sunni insurgents owned entire neighborhoods and key areas beyond. Iraq’s government was adrift, and U.S. commanders weighed the real possibility of being trapped in a full-scale civil war.

Washington’s response was “the surge,” launched Feb. 14, 2007, with the 82nd Airborne as the vanguard of an American troop buildup that would climb to 30,000 extra U.S. soldiers by the summer.

A year later – through a mix of military might, new allies and some fortunate timing – Iraq looks very different.

The crackdown in Baghdad and surrounding areas was seen as a last ditch effort to salvage the American mission in Iraq and, in the words of President Bush, give Prime Minister Nouri al-Maliki “breathing space.”

The concern now is how to build on the gains as the surge forces are pulled back, and some major challenges appear far from any clear answers: whether Iraq’s Shiite majority will further fray into rival factions and how much Iran will exert its considerable influence.

Al-Maliki’s government is still struggling to get firm footing but has recently tried to push through some of the U.S.-demanded political reforms for reconciliation.

The U.S.-led forces have successfully tamped down violence, and the Pentagon has forged critical pacts with Sunni fighters against al-Qaida in Iraq, which is trying to regroup in northern parts of the country.

After a sharp initial spike in military and civilian casualties, the numbers make a strong case that the surge generally accomplished its main goal.

Before February 2007 was out, 1,801 Iraqis and 81 U.S. soldiers would die. By contrast, January 2008 saw figures of 609 and 39, respectively.

The bulk of the surge troops are expected to be pulled out by summer. On Monday, Defense Secretary Robert Gates endorsed taking another assessment of Iraqi security in midyear before deciding on any further cuts in U.S. troop strength.

Anbar province, which stretches to the Saudi Arabian, Jordanian and Syrian borders west of Baghdad, fell virtually silent. It had been the heart of the Sunni insurgency and a bastion for al-Qaida in Iraq.

The Americans got lucky there. Sunni tribal leaders who had been fighting the Americans began in late 2006 to turn on al-Qaida, fed up with the terrorist organization’s brutality and austere brand of Islam.

U.S. forces quickly exploited the shift and began sponsoring similar movements in Baghdad and regions to the north and south. An estimated 80,000 members of the so-called Awakening Councils or Concerned Local Citizens are now fighting with – not against – U.S. and Iraqi forces.

Many of the new allies are on the American payroll, taking home minimal salaries while the U.S. tries, with limited success, to persuade the al-Maliki government to bring them into the army, police and a civilian corps of workers to rebuild the shattered country.

Into that mix, radical anti-American Shiite cleric Muqtada al-Sadr placed a freeze on his feared Mahdi Army militia, causing a dramatic fall in death-squad killings in the capital and in attacks on American forces.

The first half of the surge year saw enough casualties to make 2007 the deadliest for American troops, with 126 killed in May alone, along with 2,155 Iraqis. In all, at least 831 Americans have died in 12 months of the surge.

The sharply lower figures for the second half of 2007 have only returned the pace of U.S. losses to what they were in late 2003 and early 2004. The Iraqi death toll is back down to where it was at the close of 2005.

What’s more, much of the key legislation designed to spur reconciliation among Iraq’s Sunni and Shiite Arabs and the Kurds still languishes, with the Shiite al-Maliki either too politically weak or disinclined to take major steps toward a greater Sunni role.