More efforts are needed to develop well-considered and broadly supported plans to secure nuclear weapons in volatile regions.

Nuclear reactors are likely terrorist targets and not enough is being done to protect them.

It is inconceivable that Kim Jong Un would give up the weapon that places his nation in the exclusive nuclear club, and sanctions won't force him to do so.

The inherent danger in possessing nuclear assets becomes far more acute in a combat zone, such as today's Middle East, where nuclear materials and weapons are at risk of theft, and reactors can become bombing targets.

Twenty-eight years after its Chernobyl nuclear plant exploded, Ukraine confronts a nuclear specter of a different kind: the possibility that the country's reactors could become military targets in the event of a Russian invasion.