“Under no circumstances should this country surrender our gun rights to the control of the United Nations,” Manchin said. “While we can work toward improving the regulation of the international trade of weapons, I am very concerned that the rights of law-abiding Americans would be violated by entering into this agreement.”

Manchin convinced four of his Democratic colleagues to join Republicans in signing the letter — Sens. Mark BegichMark Peter BegichPerez creates advisory team for DNC transition The future of the Arctic 2016’s battle for the Senate: A shifting map MORE (Alaska), Kay HaganKay HaganLinking repatriation to job creation Former Sen. Kay Hagan in ICU after being rushed to hospital GOP senator floats retiring over gridlock MORE (N.C.), Mary LandrieuMary LandrieuYou want to recall John McCain? Good luck, it will be impossible CNN producer on new O'Keefe video: Voters are 'stupid,' Trump is 'crazy' CNN's Van Jones: O'Keefe Russia 'nothingburger' video 'a hoax' MORE (La.) and Mark PryorMark PryorMedicaid rollback looms for GOP senators in 2020 Cotton pitches anti-Democrat message to SC delegation Ex-Sen. Kay Hagan joins lobby firm MORE (Ark.) are all up for tough reelection races in 2014 in red states.

“We write to express our concern and regret at your decision to sign the United Nations’ Arms Trade Treaty,” senators wrote. “We urge you to notify the treaty depository that the U.S. does not intend to ratify the Arms Trade Treaty, and is therefore not bound by its obligations.”

Secretary of State John KerryJohn Forbes KerryFor the sake of national security, Trump must honor the Iran deal Bernie Sanders’s 1960s worldview makes bad foreign policy DiCaprio: History will ‘vilify’ Trump for not fighting climate change MORE signed the treaty last month, saying it wouldn’t harm the rights of U.S. gun owners.

The ATT aims to regulate the nearly $70 billion global trade in conventional arms, but all treaties must be ratified by the Senate. It seems unlikely that Obama has the votes since 53 senators voted in opposition to the treaty as an amendment to the budget resolution in March and a super-majority must ratify treaties.

All Senate Republicans signed the letter with the exception of Sen. Mark KirkMark KirkGiffords, Scalise highlight party differences on guns Stale, misguided, divisive: minimum wage can't win elections Immigration critics find their champion in Trump MORE (Ill.), whose home state has some of the highest levels of gun violence in the nation.