Russian-backed rebels in eastern Ukraine and Russian troops there have renewed their offensive in an effort to expand their hold on the oblast of Donetsk and to seize the Ukrainian Sea of Azov port city of Mariupol as part of opening a land bridge from Russia to Russian-occupied Crimea. In response to this, western European leaders and President Barack Obama are making noises about extending existing sanctions and, perhaps, broadening them to include cutting Russia off from the international financial system. In response to this, Russia threatens.

Prime Minister Dmitry Medvedev said on Jan 27 that if Russia is cut off from the Swift international payment system as punishment for its actions in Ukraine, its response “will know no limits.” Andrei Kostin, the head of VTB, Russia’s second-largest bank, said excluding Russia from Swift would mean “war.” Igor Ivanov, the former foreign minister, said that a confrontation could involve nuclear weapons.

These are people with whom negotiation is impossible, with whom a negotiated withdrawal of Russia from Ukraine cannot be had.

Threats such as these should make any response impossible other than cutting Russia off from Swift, promptly. And arming Ukraine so they can defend themselves from this Russian aggression.