"One hopes Mr. Obama wouldn't be so eager to come to Mr. Putin's rescue."

"If the rumors are a Kremlin hoax, the U.S. should publicly shoot them down as quickly as possible. To allow them to spread would be a display of weakness — the kind that a bully like Mr. Putin is always eager to exploit. Back in 1961, the perceived weakness of young President John F. Kennedy at his Vienna summit with Soviet Premier Nikita Khrushchev led indirectly to the Cuban missile crisis. Only when Kennedy showed resolve did the Soviets later back down."

Writes Garry Kasparov in the WSJ.