The last hemispheric gathering, in Argentina in 2005, was marred by riots and fierce demonstrations against then-U.S.President George W.Bush.

VOA: standard.2009.04.19

The agreement to be signed Thursday replaces the START-1 treaty, which U.S.President George H.W.Bush and Soviet President Mikhail Gorbachev signed in 1991.

VOA: standard.2010.04.04