Ambassador Boyden Gray spoke on CNBC’s Kudlow Report about the U.S. response to Russia’s aggression in the Ukraine on Friday.

Gray said beefing up the NATO military presence in Eastern Europe could be helpful but would require virtually unanimous support from Europe. The tough stance German Chancellor Angela Merkel has recently taken toward Russia gives hope for strong show of European unity.

Sanctions against Russian oligarchs would be sensitive and effective, but energy is even more important. European gas stockpiles can be redirected to Ukraine if Russia tries to play games with Ukraine. Germany can turn its nuclear power plants back on and reduce its own need for natural gas.

Ambassador Gray said that President Obama should expedite permitting of U.S. natural gas exports (a point that Ambassador Gray pressed in his Senate testimony last week) but cautioned that natural gas from the U.S. is not a substitute for other things Europe must do to reduce its dependence on Russian gas imports. Europe should intensify prosecution of antitrust charges against the Russian monopoly Gazprom.