U.S. Withdrawal
Open Skies treaty.
Intermediate-range missile treaty
Anti-ballistic missile treaty

U.S. Not ratified
Nuclear-weapons free zone in Central Asia
Nuclear-weapons free zone in Latin America
Nuclear-weapons free zone in South-east Asia
Nuclear-weapons free zone in Africa
Missile data sharing
Strategic Offensive Reductions Treaty

Going forward

The United States is urging countries that have ratified a U.N. treaty to ban nuclear weapons to withdraw their support as the pact nears the 50 ratifications needed to trigger its entry into force, which supporters say could happen this week. The U.S. letter to signatories, obtained by The Associated Press, says the five original nuclear powers — the U.S., Russia, China, Britain and France — and America's NATO allies "stand unified in our opposition to the potential repercussions" of the treaty.

It says the treaty "turns back the clock on verification and disarmament and is dangerous" to the half-century-old Nuclear Nonproliferation Treaty, considered the cornerstone of global nonproliferation efforts.

"Although we recognize your sovereign right to ratify or accede to the Treaty on the Prohibition of Nuclear Weapons (TPNW), we believe that you have made a strategic error and should withdraw your instrument of ratification or accession," the letter says.

Related treaties U.S. never signed
Arms Trade Treaty
Convention on cluster munitions
Anti-personnel mine ban