I think this may indeed happen. The US will provide support and cover for the attacks and has already provided the means. Thus, while they cannot spare the troops to attack Iran directly, they will seek to cause huge damage to Iranian infrastructure in the name of destroying nuclear facilities.
They will also step up attempts to destabilise the regime by sending in rebels to foment strife in the region. The approach is risky but IMO the military-corporate complex of the US will pursue its agenda irrespective of who is in power and the human cost. After all those Iranian oil fields need to be recovered to feed their insatiable appetite.