President George W. Bush and Russian President Vladimir Putin sign the Strategic Offensive Reductions Treaty (SORT), known as the Moscow Treaty that will reduce strategic nuclear weapons by about two-thirds to between 1,700 and 2,200 warheads by Dec. 31, 2012. (The treaty entered into force June 1, 2003.)
The U.S. began extensive air and artillery strikes against Islamic State group targets in Syria on Dec. 19 in retaliation for the killing of three Americans on Dec. 13 by a gunman affiliated with ISIS, U.S. officials said.
