The ISG and the US Institute of Peace recommend the US stay in Iraq and hand over power in 5 years. They advise a gradual troop reduction by 50% by 3 years. It also warns the US of Iranian attempts to control Iraqi politics.
That’s about right. The Pentagon is projecting roughly the same figures over the same time period. Partisan rhetoric aside, there is general bipartisan support for this strategy.
The goal, remember, is establish a state ally. The foundation is already set, so now the US just has to play caretaker until the Iraqi government is fully capable. Now that Iraq actually has its own Army and police, US Forces will gradually transfer responsibilities to them while continuing to supply and train Iraqi security forces. Americans shouldn’t have too much interest in the internal affairs of Iraq – so let’s put aside idealism.
Americans will remain nearby at isolated bases and reinforce the Iraqis if needed. The US has several permanent bases in Iraq to deter Iranian expansion into the region – so the US will likely remain in the country for decades as it has done with Germany and South Korea.