Since becoming secretary of state more than three years ago, John Kerry has been a man on a mission — multiple missions, in fact — relentlessly traveling the globe in search of diplomatic solutions to the world’s toughest problems.

His efforts have been daring and, at times, quixotic. He was no more successful than his predecessors in securing a lasting Israeli-Palestinian peace agreement. But without his persistence, the Iran nuclear deal in 2015 and last December’s global climate change agreement in Paris would almost certainly have been unattainable.
. . .
. . .there has been something honorable, even heroic, about the persistence, hard work and faith in diplomacy that this decorated Vietnam veteran and former head of the Senate Foreign Relations Committee has brought to his search for peaceful solutions.

Even as President Obama sought to keep America out of new military entanglements, Mr. Kerry has been determined to keep the nation engaged diplomatically and lead the world toward constructive results, despite times when the problems seem intractable. At 72, he is unlikely to run for office again, which gives him a certain freedom to swing for the diplomatic fences, although it may end in failure.