The Russian occupation of Crimea has challenged Mr. Obama as has no other international crisis, and at its heart, the advice seemed to pose the same question: Is Mr. Obama tough enough to take on the former K.G.B. colonel in the Kremlin? It is no easy task
. Chancellor Angela Merkel of Germany told Mr. Obama by telephone on Sunday that after speaking with Mr. Putin she was not sure he was in touch with reality, people briefed on the call said.
“In another world,” she said.