The U.S. has told Iran that the Iraqi Shia militias being supported by Iran (the Sadr and Badr organizations) are going to get taken apart soon, and Iran is well advised to back off when this happens.
Could we just be trying to scare Iran into backing off enough to take down their people inside Iraq? We are going to talk to the Iranians about Iraq.
As I've written, we just don't know when Iran will go nuclear. Perhaps our government has reason to believe we really do have a couple years to act against Iran .
And gearing up without striking now will make it easier to gain surprise when we actually do attack. Desensitize them to our actions, ya know?
Or we might be going soon. I just don't know.
UPDATE: Ok. I think we (the Iraqi government with our support) are getting ready to take down Sadr and related thugs. After years of just referring to them as "militias" we have taken the effort to define more precisely who we want put out of business. From Lieutenenat General Dempsey in Iraq:
That militia problem or, as I've really chosen to start calling it now, the extragovernmental armed groups, to separate them from the legitimate or at least recognized militias -- that's something the new government's got to take on with some immediacy as soon as they get seated.
When you take the time to refine your definitions it is because you think the distinctions are important. At the end of the day, the legitimate militias will remain and we will take down the extragovernmental armed groups.