The United States attributes the worsening of relations to the 1979–81 Iran hostage crisis, Iran's repeated human rights abuses since the Islamic Revolution, different restrictions on using spy methods on democratic revolutions by the US, its anti-Western ideology and its nuclear program.

Several senior IRGC commanders have been killed in air strikes in Syria in recent months. The IRGC channels arms and equipment, including high precision missiles, through Syria to Hezbollah. Israel is trying to stop these deliveries, as well as seeking to prevent Iran from strengthening its military presence in Syria.

Before traveling to Iran, please consider the current Travel Advisory. The Travel Advisory for Iran is Level 4, Do Not Travel. The Department of State recommends U.S. citizens do not travel to Iran due to the risk of terrorism, civil unrest, kidnapping and the arbitrary arrest of U.S. citizens.

American views toward Iraq were not enthusiastically supportive in its conflict with Iran, and activity in assistance was largely to prevent an Iranian victory. This was encapsulated by Henry Kissinger when he remarked, "It's a pity they both can't lose."