So Much for the Domino Theory

Do you remember the domino theory used to justify the war in Iraq? By using our muscle and toppling Saddam, we would set in motion a wave of democratization that would sweep the region.
The president arrived in Baghdad earlier this week for a rousing welcome from the Iraqi government. Too bad it wasn't our president, but Iran's.
Daniel Schorr spoke of the implications of this visit last night on NPR's All Things Considered:

Iranian President Mahmud Ahmadinejad visited Baghdad this week to show Iran's support for the Iraqi government. The visit can be seen as a major diplomatic setback for the United States.

The Economist reached to a similar conclusion:

The presidential visit—the first by any regional head of state since the American invasion five years ago—is only the latest sign that Iran is now the most influential of Iraq's neighbours, pushing aside nearby Sunni Arab states from which Iraq's Shia leaders still keep their distance.

Back in 2005, I heard Wes Clark say that one outcome of the war could be that Iraq could become a buffer state for Iran.
Unintended consequences? Perhaps, but hardly unanticipated.