Russia’s massing of military power near Ukraine was certain to dominate the December 7 video conference between Presidents Biden and Putin. A Russian assault would turn into a bloody affair (for Russians and Ukrainians alike) and plunge relations between Russia and the West deeper into crisis. Is Putin prepared to take that step?  Perhaps even he has not yet decided.

By all appearances, Biden did what he had to do. He spelled out for Putin the costs that would ensue if Russia attacked. These include more painful Western economic sanctions, more military assistance for Ukraine, and a bolstering of NATO’s military presence in the Baltic states and Poland. Moreover, he strengthened his hand by consulting the day before with the leaders of Britain, Germany, France and Italy.  That meant he could talk to Putin on the basis of a consolidated Western position.

Biden also described a way out of the crisis: de-escalation and dialogue, or dialogues, to address the Russia-Ukraine conflict in Donbas and broader European security questions. Neither of those discussions will prove easy. For example, NATO will not, and should not, accede to the Kremlin’s demand that the alliance renounce its "open door" policy on enlargement. But diplomacy is all about finding ways to defuse such difficult problems.

Did Biden succeed? That remains to be seen. One thing to watch is whether Moscow’s recent over-the-top rhetoric moderates. Of course, the more important signal would come from the movement of Russian troops away from Ukraine and back to their regular garrisons.

Read more views on what the Biden-Putin video call means for the regional security situation on Atlantic Council.