According to Jack Lew, the U.S. planned sanctions so as to minimize collateral effects and aim them at the people closest to the decision-making process. The U.S. Secretary of the Treasury deemed sanctions to be very efficient.
Jack Lew added that it was hard to make accurate assessment of the impact caused by sanctions, but, given the rapid oil prices plunge, many factors were harming the Russian economy at once.
The U.S. senior official stressed that the Russian economy was in far worse shape than it would be if sanctions did not work. He said that the sanctions caused considerable collateral damage in Russia.