Despite nearly collapsing intense military clashes between Azerbaijan and Armenia in early April, the OSCE Minsk Group’s mediation of the Nagorno-Karabakh (NK) conflict may be back on track, thanks to the May 16 meeting in Vienna between Presidents Aliyev and Sargsian.  That meeting’s achievements included concrete measures to restore and preserve a ceasefire, plus agreement by the two presidents to meet again in late June. With equal significance U.S. Secretary of State John Kerry participated in the meeting along with Russian Foreign Minister Sergey Lavrov, thereby restoring high-level U.S. engagement within the Minsk Group. Kerry’s participation in Vienna marked a welcome departure from Washington’s strategic retrenchment in early April. At that time, the U.S. ceded the diplomatic field to Russia: the White House issued no statement on this most serious military flare up around NK in over 22 years, while the State Department issued a bland official reaction echoing previous condemnations of relatively minor ceasefire violations.  In sharp contrast, Russian President Putin engaged intensively with Baku and Yerevan, but divorced from Russia’s fellow Minsk Group Co-Chairs, the U.S. and France.  On April 5, Putin spoke on the phone with his Azerbaijani and Armenian counterparts, then dispatched Ministers of Foreign Affairs Lavrov and Defense Shoygu to Baku and Yerevan, with a follow up visit to both capitals by Prime Minister Dmitiry Medvedev. Furthermore, on April 5, Chief of the Russian General Staff Gerasimov brokered a new ceasefire with his fellow military chiefs from Armenia and Azerbaijan, without the presence of the Minsk Group Co-Chair Ambassadors. By not checking the Kremlin’s go-it-alone approach, (which was unthinkable during my time as the U.S. Co-Chair of the Minsk Group during 2006-2009), Washington fed an impression that Russia was filling a diplomatic vacuum, and leaving Aliyev and Sargsian alone with Putin. This perception, cultivated by Putin, risked undermining the credibility of the OSCE’s entire mediation effort, thereby increasing the likelihood of future military clashes, and even war. Thanks to Secretary Kerry’s participation in Vienna, however, the U.S. reestablished its powerful presence in the Minsk Group.  If Secretary Kerry sustains this engagement, the prospects for actually implementing the de-escalatory measures agreed in Vienna will be significantly greater.  Moreover, the psychological climate could improve sufficiently to enable Presidents Aliyev and Sargsian to enjoy a successful discussion in late June. Success at this next presidential meeting, however, will not include a breakthrough on a political settlement of the conflict, given the rawness of emotions between Baku and Yerevan.  More realistically, perhaps Presidents Sargsian and Aliyev will salve their diplomatic wounds and agree to subsequent meetings, where they might define further de-escalatory steps.  These could include redeployment of heavy weapons away from the Line of Contact to their original positions in the heartlands of Azerbaijan and Armenia, thereby reducing the risk that a sniper incident or modest provocation might inadvertently devolve into full-scale war. If the presidents build and then sustain such momentum, the Minsk Group Co-Chairs could restart serious discussions of a political settlement of the NK conflict. A mid-term breakthrough would be to finalize the basic principles of a comprehensive settlement, as outlined by the “Madrid Document” of December 2007.  The two sides accepted the Madrid Document in principle in January 2009, though never formally so.  That document’s basic principles include Armenia’s withdrawal of its troops from all seven Azerbaijani territories they occupy (in accordance with four UN Security Council Resolutions); Azerbaijan’s acceptance of an “interim legal status” for NK; agreement that a vote by the residents of NK will take place at some future date; establishment of a corridor connecting NK to Armenia; and deployment of an OSCE-led international peacekeeping contingent. Though agreement on this full package is impossible in the near future, Presidents Sargsian and Aliyev might be sufficiently sobered by April’s brush with all-out war to agree to work toward intermediate steps.  These might include Armenia agreeing to withdraw its forces from portions of the seven occupied Azerbaijani territories if Azerbaijan announces it accepts a definition of NK’s interim legal status. For now, however, speculation about progress toward a political settlement is premature.  Simply developing a positive psychological climate between the two presidents will be a tall order, and require Secretary of State Kerry’s active support; political cover from the White House will also be crucial. Otherwise, Presidents Aliyev and Sargsian will remain overly cautious, intent on avoiding perceptions at home of strategic softness, military timidity, or vulnerability to Putin’s unilateral diplomacy. Based on his reaction (or lack thereof) to April’s unprecedented military clashes, President Obama will be reluctant to engage in this way.  But, ignoring current opportunities to reenergize the Minsk Group at the highest political level will doom hope for a negotiated political settlement. Left with no alternative to break a status quo it finds unacceptable, Azerbaijan will focus increasingly on a military option. This would risk a regional war, which could pit NATO Ally Turkey with Azerbaijan against Russia-allied Armenia — and with Iran lurking next door.  Avoiding this nightmare scenario should make serious engagement seem worth the trouble for the White House. More by the author on Karabakh conflict https://www.washingtonpost.com/opinions/nagorno-karabakh-conflict-is-too-dangerous-to-ignore/2016/04/11/1e32fc44-ff23-11e5-9d36-33d198ea26c5_story.html The views expressed in this article are those of the author alone and not Caspian Policy Center.