The president also deserves credit for showing, once again, how bold and effective U.S. leadership can pave the way for multilateral efforts. He has been right to insist that others take their fair share of the burden, but he has also made clear that American leadership was essential, even indispensable.

This was a Kennedy-esque speech.

Robert Kagan writes a monthly foreign affairs column for The Post, and is a senior fellow at the Brookings Institution. Kagan served in the State Department from 1984 to 1988.