On Sunday, Ukrainian naval vessels entered waters claimed by Russia near Crimea, leading the Russian Coast Guard to fire on and seize three Ukrainian ships. Ukrainian President Petro Poroshenko has responded by declaring martial law and putting the army on full alert, declaring, “Ukraine is under threat of full-scale war with Russia.”

The ongoing crisis is the most significant direct military confrontation between Russia and Ukraine, the countries with the two largest standing armies in Europe, since early 2014, when a far-right coup in Kiev, orchestrated and financed by the European Union and US imperialism, plunged the region into a state of perpetual crisis.

The standoff in the Azov Sea is the latest in a series of provocations staged by US imperialism and its allies—from the coup in Ukraine itself, to the numerous alleged gas attacks in Syria, to the Skripal poisoning, to alleged Russian “meddling” in the US elections—aimed at creating the pretext for sanctions and military aggression against Russia.

As with every provocation by the Poroshenko regime against Russia in recent years, NATO, the EU and the US immediately took the side of Ukraine in the current confrontation, decrying Russia’s action as an act of “aggression” and “violation of international law.”

Washington’s hypocrisy knows no bounds. Just one day earlier, the Trump administration had whitewashed the brazen murder of Saudi journalist Jamal Khashoggi, declaring there was no evidence that the Saudi crown prince had done anything wrong.

Poroshenko announced that US Secretary of State Mike Pompeo had assured him Washington would provide “full support, full assistance, including military assistance.”

Ukraine’s provocation comes just days before a planned meeting between US President Donald Trump and Russian President Vladimir Putin at the G20 summit in Argentina, to be held on Friday and Saturday.

The Democratic Party-aligned media, which for more than two years has been engaged in a hysterical campaign against Trump on the basis of his alleged “soft” stance on Russia, immediately seized on the incident to pressure the US president to “stand up to Putin,” as the New York Times put it.

In an editorial published Wednesday, the Times called on the US and its allies to “impose stronger sanctions, bar their ships from entering Russian ports in the Black or Azov Seas or increase military support for Ukraine.” It acknowledged that “these actions all carry risk,” without spelling out the danger of a military confrontation that could quickly involve the world’s two biggest nuclear powers.

The Washington Post, for its part, declared, “Mr. Putin’s aggression ought to affect the reception he receives from Mr. Trump at the G20 summit in Buenos Aires... Mr. Trump could send a message by refusing to meet Mr. Putin; if he does go ahead with a bilateral meeting, he ought to begin it by telling the Russian leader that his assault on Ukraine is unacceptable and will have consequences.”

Elements within the US state and the corporate media are determined to prevent a repetition of this summer’s Helsinki Summit, which triggered denunciations of Trump as a “traitor” and “Russian agent.” Since then, the Trump administration has pulled out of the INF Treaty with Russia, which prohibited both countries from developing short- and medium-range nuclear missiles.

Poroshenko manufactured this crisis just a few months before presidential elections in Ukraine, which the unpopular president is almost certain to lose. The declaration of martial law gives Poroshenko and the military sweeping powers, including the right to raid apartments and search cars, curtail press freedom, censor the internet and ban demonstrations. Poroshenko’s actions are directed at Ukraine’s own population no less than at Russia.

As a result of this week’s events, Ukraine and Russia are now on the brink of a major war that could quickly draw in the imperialist powers. Time magazine wrote that the Azov Sea crisis had the potential of becoming a second Gulf of Tonkin crisis, which became the pretext in 1964 for the direct involvement of the US military in Vietnam.

On Wednesday, Russia announced that it would deploy another S-400 surface-to-air missile system to Crimea. Russian media have warned of a “major war” that would cost thousands of lives on both sides.

The Azov Sea crisis fully confirms the warning made by the International Committee of the Fourth International in 1991 that the dissolution of the Soviet Union would open up a new historical period of imperialist wars. The undermining of Russia’s influence in the Black Sea region, which has historically been of major geostrategic significance to Russia as a water gateway to the Mediterranean and the energy-rich Middle East, has been a central component of US imperialism’s efforts to bring all the resources of the vast landmass previously covered by the USSR under its direct control.

If in 1991 Turkey was the only NATO member-state bordering the Black Sea, today all states bordering the Black Sea except for Russia itself are either NATO members or have right-wing, anti-Russian and pro-US regimes that were installed by imperialist-orchestrated “color revolutions” (Ukraine and Georgia).

The Putin regime has no answer to the ever-increasing pressure of imperialism except a combination of attempts to strike a deal and the whipping up of nationalism and militarism at home. As the direct outcome of the Stalinist destruction of the Soviet Union, this regime, representing a criminal oligarchy, fears a movement of the Russian working class more than anything else, including a potential assault by imperialism.

The extraordinary recklessness of the imperialist warmongers and their far-right stooges in Eastern Europe can be explained only by the profound crisis of US and global capitalism and the growth of the class struggle. This year has seen an upsurge of working class struggles in Iran, India, Europe and the United States, the center of world imperialism.

These struggles provide the material basis for opposing the war aims of US imperialism. What is required is the building of sections of the International Committee of the Fourth International, including in Ukraine and Russia, as the leadership of a socialist anti-war movement of the international working class.