With prayer and song, dozens of supporters saw anti-nuclear weapons campaigner Susan Crane back to prison.
The 71-26 vote marked a significant foreign policy achievement for the Obama administration during the lame-duck Congressional session.
Senate Republicans appeared increasingly determined to use the nuclear treaty as a political football in their drive to block all possible administration initiatives.
Marking the 65th year since the first atomic bombs were dropped on Hiroshima and Nagasaki, Japan, vigils were held on the New Haven Green at time the bombs were dropped on August 6 and 9.
President Obama introduced a new nuclear weapons policy Tuesday with the aim of reducing nuclear weapons and a promise that America would no longer build them.
The U.S. and Russia are close to an agreement that will make major cuts in their nuclear stockpiles. It is seen as a step in the direction of complete nuclear disarmament.