US Iran relations are strained over a variety of issues including Iran's backing of terrorist groups, the activities of the Islamic Revolutionary Guard Corps and its nuclear activities.
The U.S. has long charged Iran with backing groups it classifies as terrorist, including Hamas, Hizballah and Palestinian Islamic Jihad.
Since 1979, Iran has maintained a special military force to "protect" the goals of the revolution, which includes exporting it. According to most accounts, this force is also responsible for training terrorist groups, which is why the U.S. wants it classified as a terrorist group itself.
Iran claims that its nuclear development program is for civil use only. The US doesn't believe it. A timeline shows the history of Iran's program, and of the US, European and UN efforts to stop it.
As of 2008, Iran is already under the force of multiple sanctions. Yet it continues its nuclear program. This article weighs the pros and cons of even more sanctions.
Iran is a contentious issue in the 2008 presidential elections. Obama's and McCain's different approaches are explained.