The Russian war against the Ukraine has some unique features. Ukraine has been invaded and controlled by the units of the Armed Forces of the Russian Federation. From the perspective of international law, it should be undoubtedly called a crime of aggression:
The devious methods used by political and military leadership of Russia to cover the armed invasion of the Ukraine (operations of special units; the units and equipment of the regular Russian army without insignia, which were sent to Ukraine, the use of civilians, including women and children, as human shields in the takeovers of Ukrainian military bases and the financing and supply of arms to mercenaries; Subversion of Russian secret services; the use of propaganda mechanisms and more) aggravate the responsibility of Russia as aggressor.
For the first time beginning with Crimea, Russian soldiers without insignias took control of strategic positions and infrastructure within the Ukrainian territory of Crimea. The fact that a State has used the first force against another state, is the most important main criterion of aggression. Article 2 of General Assembly resolution 3314 of the United Nations, "Definition of Aggression”, which was adopted on 14 December 1974 represents "The first use of armed force by a State in contravention of the Charter shall constitute prima facie evidence of an act of aggression ". According article 3 of UN General Assembly Resolution 3314: “There is no legal significance whether the war was officially declared, it is subject to and in accordance with the use of armed force by a State against another qualify as an act of aggression.
Invasion of the Russian armed units and troops without insignia, blockade of the Ukrainian ports with ships of the Ukrainian Navy by the Russian Black Sea Fleet, recruitment and arming of the locals at irregular mercenary bands, the use of these groups together with the based on the territory of Ukraine according to the Agreement on Russian Black Sea Fleet units to blockade of Ukrainian military bases; and military occupation of the Crimea. Use of force by the armed forces of Russia in March 2014 in the Crimea including the invasion of the Russian armed units and troops without insignia, blockade of the Ukrainian ports with ships of the Ukrainian Navy by the Russian Black Sea Fleet, and military occupation of the Crimea (2014 Russian Military Intervention in Ukraine, Wikipedia) correspond to the definition of aggression by ICC Statute Art8.2 following:
(a)The invasion or attack by the armed forces of a State in the territory of another state, or any military occupation, however temporary, resulting from such invasion or attack, or any annexation by the use of force of the territory of another State or part thereof
(c)The blockade of the coasts or ports of a State by the armed forces of another State
(e)The use of the armed forces of a State which are within the territory of another State with the agreement of the receiving State, in contravention of the conditions provided for in the agreement, or any extension of their presence in such territory beyond the termination of the agreement. The actions of the Russian Federation in Ukraine, which are committed in the February-March 2014 correspond to paragraphs "a", "c" and "e" of Article 8.2 and should therefore as act of aggression to be qualified.
The second phase of the Russian aggression against Ukraine began in March 2014 when pro-Russian and anti-government groups took place in the Donetsk and Luhansk oblasts of
Ukraine, together commonly called the "Donbass. The self-appointed leaders (many of whom are Russian citizens) performed an illegal sham referendum on the secession of these illegitimate territorial units of Ukraine. They have taken part in the storming and occupation of the administration building in many cities and towns in Donetsk and Luhansk regions. Armed gangs were with Russian mercenaries and weapons and military equipment, including tanks, artillery. Russian soldiers were captured in Donetsk Oblast; Russia claimed that they had crossed over by accident. (2014 Russian Military Intervention in Ukraine, Wikipedia). Russian violence by its forces between April - July 2014 in Donetsk and Luhansk regions meet the criteria of an act of aggression that are listed in ICC Statute Art 8.2 defines an act of aggression of the following actions:
(b)Bombardment by the armed forces of the State against the territory of another State or the use of any weapons by a State against the territory of another State
(d) An attack by armed forces of a State on the land, sea or air forces or marine and air fleets a different state
(g)The sending by or on behalf of a State of armed bangs, irregulars or mercenaries which carry out acts of armed force against another State…
Russia, unfortunately, presents itself as a barbaric power of the past, the openly disregarded the requirements of the modern international law and the civilized rules of behavior. Not only the Ukraine is threatened, but also the existing international order. Ukraine is waging a war of self-defence against an international aggressor – the Russian Federation. Russia invaded the territory of Ukraine - Crimea, Donetsk and Lugansk so far - and attacked Ukrainian forces without any legal justification; bombed the territory of Ukraine and many Ukrainian citizens were killed; and seized the territory that belongs within the internationally recognized borders of Ukraine, declaring it part of Russia. It is certainly arguable that the people in the Crimea have a distinct identity and territory, created over centuries and fostered by decisions of Russia and Ukraine. It is not unlawful for it to have a referendum and declare itself independent or that it wishes to merge with Russia, as this was justified by the International Court of Justice