“Further provocations will achieve nothing … except further isolation.” So said President Obama as the U.S. and E.U. slapped sanctions on Russia and froze the assets of Putin’s cronies following the weekend’s vote in Crimea.

+ One of the officials targeted by the asset freeze mocked the sanctions on Twitter (where else?).

+ “Vladimir Putin, in his campaign to restore Russian dominance over post-Soviet states, has an unconventional weapon in his arsenal: vast supplies of natural gas.” The New Yorker’s James Surowiecki on Putin’s Power Play.

+ Buzzfeed: A 22-step-guide to understanding how Crimea voted to join Russia and why Eastern Ukraine might be next.