What are reasons for and against going to war in Iran?

Answer 1

Assuming the question is: "What are the pro/cons for the United States to go to war with Iran now (2010)?", here are some reasons:

(note that all reasons are from the United State's viewpoint, which by its very nature, is biased. Also note that not all reasons may be sound, and/or work out as well as hoped)

Arguments for the US starting a war:

• Iran is almost certainly developing nuclear weapons. Allowing Iran to possess nuclear weapons will destabilize the Middle East, and possibly allow nuclear weapons into the hands of terrorists. Invading Iran would prevent Iran from acquiring such weapons.
• Iran is oppressing its population severely. As evidenced by the repression following the last major election, the Iranian people wish to change their government, but the armed theocratic thugs in charge refuse to relinquish power. A US invasion would topple the current government and allow the Iranian people the ability to freely choose their government.
• The current government hates the United States. An invasion which led to a change of government would almost certainly lead to one much more friendly towards US views.
• Iran contains vast oil supplies. Invading Iran (and changing its government) would likely free up most of that oil for use by the United States.
• Iran is a sponsor of terrorism. An invasion would force them to stop supporting many terrorist organizations.
• An Iranian government which did not sponsor terrorism and which was at least neutral towards US viewpoints would significantly reduce tensions in the Middle East. In particular, it would likely make solving the Israeli-Palestinian problem simpler.

Reasons against the US starting a war:

• The current US ground forces are heavily committed in both Afghanistan and Iraq. Starting a wholesale invasion of Iran would be extremely difficult without significant allied support.
• Allied military support of a US-led invasion of Iran is very unlikely. Particularly for getting additional ground forces.
• An aerial-only war would be unlikely to win, and likewise would fail to gain most, if not all, US war aims.
• A US-Iran war would certainly increase anti-US feelings in the world, likely highly increasing terrorist activities. It would also likely greatly complicate US international relations with many countries.
• Winning a ground campaign in Iran is difficult. The terrain is quite difficult, and Iranian forces are skilled at using civilian cover to limit attacks by US forces.
• The Iranian population may very well NOT appreciate being invaded, and rather than consider the United States a liberating force, see them as a conquering force, to be fought. This would lead to an extended guerrilla campaign, which would seriously harm many long-term US goals.
• Costs associated with yet another war are non-trivial, and the US government can ill-afford to pay them.

I'm sure I've missed some.