The UN Security Council is responsible for maintaining international peace and security (according to Art. 24 of the UN Charter) and is the only body that has the right to launch preventive and enforcement actions on behalf of the UN. Since Ukraine has suffered an armed attack by the armed forces of the Russian Federation and (or) its controlled insurgents, this conflict should be considered as armed aggression. Actions by Russia fall under the definition of aggression according to Resolution 3314 of 14 December 1974. The fact of aggression has been recognized by such organizations as PACE, OSCE Parliamentary Assembly, NATO Parliamentary Assembly. But UN Security Council, the main authority to qualify actions by Russia towards Ukraine as aggression, doomed to fail to do because of imminent Russian veto. Potentially most important intervention by UN to contribute to conflict resolution in Donbass would be the deployment of peacekeeping forces. But besides possible Russian veto, slow pace by Ukrainian government is an issue: it took almost a year for Ukrainian authorities to officially call UN and EU to dispatch peacekeepers (later turned to be defined as an assessment mission). At the moment, according to Ukraine's permanent representative to the UN V. Yelchenko, talks on this issue has not yet begun in UN because of "search for appropriate approach to the issue." Obviously, to overcome 'hidden veto" by Russia we need immense efforts. As projects of six different resolutions in SC were blocked by Russia from going for voting we should say that effect of so-called "double hidden veto" is in place � other permanent members are reluctant to move forward with new projects becase they are increasingly discouraged after facing one hidden veto after another.