The US government is under pressure from a wide range of interests, both foreign & domestic, to withdraw military forces from Iraq. This is unlikely to happen - here's why:
The USA, with close ally Israel behind & urging them forward, needs the military bases now commandeered/occupied/rented in Iraq. Most US resources have now been withdrawn from Saudi Arabia, esp. Prince Sultan Air Base. (This gave a key victory to Osama Bin Laden -- as forcing US withdrawal from Saudi Arabia was a central focus for 9/11 terrorism, where 15 of the 19 hijackers were Saudi Arabian).
The new US embassy compound in Iraq will be the world's largest embassy by far. On 104 acres (42 hectare) in the heart of Baghdad, the riverside site would fit three Pentagon buildings (that building is 29 acres plus a 5 acre central plaza) - and the Pentagon is one damn big building; the US Capitol building footprint is just four acres. How many visas they plan to issue?
US claims for staying in Iraq to install democracy seem poppycock. The duly-elected lawmakers of Iraq themselves asked for a US withdrawal timetable (8 May 2007), and have been thus far ignored. As with Guantanamo and many other US bases around the world, "y'all Irakis'd best prepare 4 permanent Aw-Q-Pay-Shun."