1. United States and China: The United States and China have been involved in ongoing trade disputes, disagreements over technology transfers, and strategic competition in the Asia-Pacific region.
2. United States and Iran: The United States and Iran have had a long history of strained relations, including the Iranian hostage crisis in 1979, the 1983 bombing of U.S. Marine barracks in Beirut, U.S. sanctions against Iran, and disagreements over Iran's nuclear program.
3. United States and Russia: The United States and Russia, formerly the Soviet Union, have a long history of rivalry, including during the Cold War. Differences have included nuclear arms control, cyber warfare, influence over former Eastern Bloc countries, and regional conflicts in Syria, Ukraine, and other areas.
4. United States and Afghanistan: The United States invaded Afghanistan in 2001 in response to the September 11th attacks. The subsequent military involvement and nation-building efforts have been contentious, and the war has been one of the longest-running conflicts in U.S. history.
5. United States and Iraq: Conflict between the U.S. and Iraq began during the Gulf War in 1990-91. U.S. intervention continued in 2003 with the Iraq War, which lasted for several years. The reasons for intervention included concerns over weapons of mass destruction, political stability, and the war on terrorism.
6. United States and North Korea: The United States and North Korea have had a tense and hostile relationship since the Korean War (1950-53). Issues include North Korea's nuclear weapons development, human rights concerns, and the broader geopolitical situation in the region.
7. United States and Israel/Palestine: The United States has been involved in mediation and peace processes related to the Israeli-Palestinian conflict for many years. There are ongoing differences in perspectives and policies regarding settlements, refugee issues, and the status of Jerusalem.
These conflicts can involve varying degrees of diplomatic tension, economic sanctions, military involvement, espionage, and diplomatic efforts. The United States plays a significant role in international diplomacy and security, engaging in both bilateral and multilateral initiatives to address these conflicts.