US sanctions to punish the Kremlin for invading Crimea and eastern Ukraine should be codified by Congress to ensure they stick.
http://www.worldaffairsjournal.org/article/how-keep-russia-sanctions-trump-proof
http://www.ej.ru/?a=note&id=30686
http://graniru.org/opinion/milshtein/m.258415.html
http://lb.ua/world/2017/01/30/357197_povestka_trampa.html
http://www.kommersant.ru/doc/3205872
http://www.rbc.ru/newspaper/2017/01/30/588e05559a7947ab0afeb385
http://www.kommersant.ru/doc/3205470
http://inosmi.ru/politic/20170130/238622317.html