So the Iraq "War" you started is going poorly, congress and the American people are telling you to change course and show some results, what can you do next? Well there's nothing like another national enemy to rally the troops and divert attention. Iran seems to fit the bill nicely. They are "supporting the insurgency in Iraq", "supporting terrorism", not to mention their nuclear program. The perfect diversion to deflect criticism of Iraq. Never mind that the United States should be building bridges to Iran to facilitate some kind of political solution in Iraq.
Health care is another one. No one can be against providing health care for more people as long as it doesn't cost more. Bush's plan is being promoted as doing that. What it really looks like is another way to make the tax code more complex and provide a tax break for the wealthy. After his State of the Union address, Bush went on the road to promote his health care plan. Never mind that the violence in Iraq is escalating and the additional troops he is sending are going into an increasingly dangerous and chaotic place.
When things go bad, just change the subject. Divert the public's attention and you can ignore all those nasty questions from the press.