Throughout the crisis in eastern Ukraine, a persistent mystery has complicated efforts to resolve a standoff that has erupted into open warfare: What does Russian President Vladimir Putin want?
In the last two days, Russian troops have attempted to relieve pressure on their separatist allies in Donetsk and Luhansk by opening what amounts to a third front south of the two breakaway cities. On Wednesday, Ukrainian troops, who had been steadily advancing on separatist forces in the east, beat a hasty retreat from Novoazovsk, where they were routed by troops and armor streaming across the Russian border. Novoazovsk lies a mere 20 miles from the southeastern port city of Mariupol, a city of 500,000.
Will Putin continue the advance past Mariupol, toward Crimea -- which he annexed in March -- and potentially all the way to the breakaway region of Transnistria in Moldova? Or is this a mere tactic to ensure the survival of Putin's proxies in Donetsk and Luhansk?
Russia has been involved both politically and militarily in the armed uprising in Ukraine since it began in April but recent developments mark a sharp escalation in the five-month war. Russian troops are now openly fighting on Ukrainian soil, even as Moscow continues denying that it has mounted what can only be called an invasion of its neighbor.
But evidence streaming out of Russia puts the lie to that claim. Here are Russian tanks moving through eastern Ukraine.
On Thursday, NATO released satellite images showing purported evidence of Russian troops armed with sophisticated weaponry on Ukrainian soil. "Over the past two weeks we have noted a significant escalation in both the level and sophistication of Russia's military interference in Ukraine," stated Brig. Gen. Nico Tak. "The satellite images released today provide additional evidence that Russian combat soldiers, equipped with sophisticated heavy weaponry, are operating inside Ukraine's sovereign territory."
Here are Russian military units, including self-propelled artillery, moving near Krasnodon, which lies southeast of Luhansk.
So what do these moves accomplish? In the short term, the Russian moves along the southern border are likely to relieve pressure on separatists in Luhansk and Donetsk, who have been gradually ceding territory to the Ukrainian army. Andriy Lysenko, a spokesman for the Ukrainian military in Kiev, said that a Russian armored column moved south of Donetsk toward Mariupol with the aim of diverting Ukrainian forces to deal with a new threat.
The capture of Novoazovsk is strategically vital due its proximity to Russia and Crimea. Consequently, the Russian military gambit raised the possibility that Moscow's troops could continue their drive west along the Ukrainian coast, carving out a swath of territory resembling a scepter stretching from Luhansk to Odessa. Such a move would connect the Crimean peninsula with the Russian mainland and allow Russian troops to push forward into Transnistria in Moldova, another Russian-backed breakaway state.
The map below, put together by Swedish defense researchers in April, outlines in white dashes what that area might look like.
Beginning with Moscow's decision to seize Crimea and later with its decision to foment unrest in eastern Ukraine, there has been element of unpredictability to Russian actions. Even as many observers have argued that Russian actions represent an effort to regain territory lost when the Soviet Union crumbled, there has been no clear evidence that Putin has made a decision to seize a large chunk of territory in eastern Ukraine and potentially find himself in a major land war.
"Putin has been throughout this crisis a bit of a gambler," said Jonathan Eyal, the international director at the Royal United Services Institute, a British think tank. "We underestimate the element of improvisation within the Russian decision-making in this crisis."
According to this line of thinking, it is imperative that Putin not be presented with any further opportunities to expand the territory under his control. If his forces are able to easily consolidate control of Mariupol and its environs, Russian troops may very well continue their drive along the Ukrainian coast, perhaps all the way to Transnistria.
Regardless of whether Putin expands the offensive, the Russian leader in the meantime achieves his short-term goal of propping up the separatists he backs. "He wants a failed, destroyed Ukrainian state and to prevent Ukraine from falling in the Western sphere of influence," Eyal said. "The strategy is to not have a strategy."
With NATO estimates putting the total number of Russian troops in Ukraine at about 1,000 and Ukrainian officials saying that two columns of tanks and military vehicles moved into southeastern Ukraine from Russia on Thursday, Moscow's forces lack the equipment and troops to mount a broader campaign toward Transnistria. According to Steven Pifer, a former U.S. ambassador to Ukraine and the director of the Arms Control and Non-Proliferation Initiative at the Brookings Institution, Russia would need on the order of 50,000 to 80,000 troops just to occupy the city of Luhansk or Donetsk. To carve out a corridor from Luhansk to Donetsk would require a vastly larger number and would place Russian troops in areas where they are likely to receive a hostile reception by the local population.
In response to the incursion, Ukrainian commanders said they have regrouped around Mariupol to more effectively defend the city. And in Kiev, Ukrainian officials said that they will reinstate mandatory military conscription.
Meanwhile in Washington, President Barack Obama said that Western nations may tighten sanctions against Moscow. "My expectation is we will take additional steps primarily because we have not seen any meaningful action on the part of Russia to try to resolve this in a diplomatic fashion," he said during a White House press conference. "The sanctions that we've already applied have been effective."
But whether Western sanctions have an effect is perhaps less important than how Ukrainian troops around Mariupol perform in the face of Russian attacks.
IVAN SEKRETAREV/AFP/Getty Images