This report discusses the reasons that Iran is considered a threat to U.S. security, including Iran's nuclear program, involvement with terrorist organizations, and involvement with neighboring countries' local governments. The report also discusses ways which the U.S. hopes to modify Iran's behavior with sanctions, and the effectiveness of these sanctions.

The Kurdish-inhabited region of northern Iraq is relatively peaceful and prospering economically, but the Iraqi Kurds' political autonomy and political strength in post- Saddam Iraq is causing friction with Arab leaders in Iraq, Turkey, and Iran. However, an overall reduction in violence in Iraq, coupled with continued U.S. political influence over the Kurds, is likely to prevent a destabilizing escalation of the Iraqi Kurd-Arab disputes. Also see CRS Report RL31339, Iraq: Post-Saddam Governance and Security, by Kenneth Katzman.

With a conventional military and weapons of mass destruction (WMD) threat from Saddam Hussein's regime removed, Iran seeks to ensure that Iraq can never again become a threat to Iran, either with or without U.S. forces present in Iraq. By supporting armed Shiite factions, Iran's influence in Iraq has at times hindered U.S. efforts to stabilize Iraq, and has heightened the U.S. threat perception of Iran generally. However, Iran faces difficult choices in Iraq now that its protege Shiite factions, formerly united, are competing and often fighting each other.