President Obama hosted dozens of world leaders in Washington for an unprecedented summit on stopping the spread of nuclear weapons. Jeffrey Brown reports on the summit and efforts to slash nuclear arsenals.

The Obama administration has rolled out a new roadmap for limiting American nuclear arsenals and promoting the goal of a nuclear-free world. Jeffrey Brown gets two points of view on arms control from nuclear experts.

In a move that could end what has long been viewed as the primary obstacle to the full implementation of a political peace deal in Northern Ireland, the IRA has destroyed its vast arsenal of weapons, independent monitors announced Monday.

By PBS NewsHour