'We are extremely disappointed," the White House press secretary said after Moscow granted asylum to fugitive NSA leaker Edward Snowden. A nice understatement. Washington is now looking at the greatest counterintelligence failure since the Rosenbergs betrayed nuclear know-how to Stalin some 60 years ago. Now the Russians have Mr. Snowden's hard disks to unearth more U.S. secrets than could be stolen by a battalion of spies.

President Vladimir Putin has it in his hands to endlessly embarrass the U.S. by releasing choice bits and pieces from the Snowden trove, or to threaten to do so to keep Washington on its best behavior. After this slap, "extremely disappointed" is the diplomatic equivalent of pouting—unbecoming to a great power.

Why did Mr. Putin decide to thumb his nose at the U.S. after playing cat-and-mouse for six weeks? Easy—because he could. He has taken the measure of Barack Obama, concluding that there isn't much there there, to paraphrase the president on the State Department's emails about Benghazi.

To continue reading Josef Joffe's op-ed in the Wall Street Journal, click here.

Josef Joffe teaches U.S. foreign policy at Stanford University, where he is also a fellow at the Hoover Institution and the Institute for International Studies. His book "The Myth of America's Decline" will be published by Norton in the fall.