Western governments have sounded the alarm that Russia is ready to attack Ukraine at any moment.
The Joe Biden administration is considering moving troops, warships and artillery to Eastern Europe and NATO has announced that member countries will send ships and planes to the region.
But how, exactly, might military action begin has become an anxious guessing game to military analysts, to Western and Ukrainian officials, and not least to Ukrainian soldiers, who are likely to be the first to know.
“I prefer to have peace,” said Ihor, a sergeant who is the Ukrainian unit’s cook, giving only his name and rank, in accordance with military rules. I have two children at home.
If a raid occurs, most military analysts agree that it won’t start with a massive show of force: tanks crossing the border or a sudden and devastating attack from the air.
Rather, it would start with an action more ambiguous and limited that Moscow would use as a justification for a broader intervention.
Such action, U.S. and Ukrainian officials say, could come in many different ways: the seizure by Russian-backed separatists of disputed infrastructure, such as a power plant, for example.
Toxic spill by “accident”?
The Luhanska Power Plant in Shchastia, Ukraine, is just a few hundred meters from the front line in the war in eastern Ukraine.
It could even start invisibly, with gas floating in the air, if Russia decided to stage an accident at an ammonia plant in this area and then send in troops under the guise of controlling it.

A militiaman stands guard in the area of fighting with pro-Russian rebels in Luhansk, Ukraine. Photo: REUTERS
That possibility was raised this month by Ukraine’s military intelligence agency.
Ukraine estimates that Russia has some 127,000 soldiers near its borders. The buildup, said Dmitry Adamsky, an expert on Russian security policy at Reichman University in Israel, “is visible enough to allow people to imagine a variety of scenarios that could happen. At the same time, it is uncertain enough to hide strategic intent.”
Russia has repeatedly denied in recent weeks that it has plans to invade Ukraine, saying it is Russia whose security is threatened by NATO exercises near its borders and arms shipments to Ukraine.
Russian tricks
Analysts say that Russia has a rich repertoire of tricks that make it almost impossible to guess a first move.
He proved this with his first foray into Ukraine in 2014. At the time, mysterious masked soldiers appeared in Crimea in a military intervention that Russia initially denied but later acknowledged.
Russian soldiers said to be “vacationing” or “volunteering” turned up in eastern Ukraine later that year. There in Crimea, Russia has its main naval base and from there it is projected to the Mediterranean so it was expected that something like this would happen.
In fact, almost every Soviet and Russian military intervention in the last half century, from the Prague Spring to Afghanistan to the war in Chechnya, began with a operation of disguise or disorientation, with the intention of sowing confusion.

Vladimir Putin’s government could order an invasion of Ukraine. Photo: REUTERS
A limited incursion could also serve Moscow’s goal of dividing NATO allies, as some countries would see the move as insufficient cause to sanction Russia and others would disagree.
Last week, Biden hinted at possible divisions within the Western alliance over how to react to a provocation that falls short of an invasion.
For soldiers in the east, where Ukraine has been fighting Russian-backed separatists for almost eight years, the lack of clarity has made the situation stressful.
“Maybe it will happen here,” said Lt. Sergei Goshko, who is responsible for civil affairs on this part of the front, and thus authorized to give his full name. “Maybe it will happen south of here.”
“But we can’t know everything,” he added. “It’s a chess game where you can’t see the moves in advance. Who will do what to whom? We don’t know,” he remarked.
In an ominous hint of how Russia could justify an invasion, its ambassador to the Organization for Security and Cooperation in Europe, Konstantin Gavrilov, said on Sunday that Moscow would respond if its citizens were threatened.
Russia has granted citizenship to tens of thousands of people on the separatist side of the eastern Ukraine conflict, any of whom could see escalation.
Ukrainian officials and American diplomats have focused on one possibility in particular in the region: an accident at one of the most dangerous industrial sites in eastern Ukraine, an ammonia gas factory in separatist-held territory a few miles from the Ukrainian front.
Ammonia is a component of fertilizers, but can be lethal in high concentrations.

Ukrainian soldiers, in the Donetsk area, where they fight with pro-Russian rebels. Photo: EFE
A chemical leak releasing a toxic plume is one of the main possibilities., which could poison soldiers and civilians on both sides of the front lines, authorities say.
It could justify, for example, a Russian deployment of emergency cleanup teams with an escort of soldiers. In December, Russian Defense Minister Sergei Shoigu said, without providing evidence, that US mercenaries had smuggled unspecified chemicals into eastern Ukraine.
With both Russia and Ukraine talking of chemical leaks in this area, local authorities have plans to sound a siren to warn civilians, though it’s unclear how they could protect themselves other than to close windows.
But a gas leak is only one possibility. Causes for the escalation in eastern Ukraine along the front abound, said Maria Zolkina, a Ukrainian political analyst, including the possibility of a limited advance by separatists to seize disputed infrastructure such as waterworks or power plants.
Naval showdown?
Hostilities could also start with a naval clash in the Sea of Azov, where Ukrainian and Russian ships operate in close proximity, or a false-flag attack targeting Russian-speaking citizens in breakaway areas.
Analysts say there could also be a the spy is clear purely political, such as a Russian claim that the United States, Britain and other NATO countries are providing weapons to Ukraine that pose a risk to Russian security.
Limited action could put political pressure on the Kiev government to agree to Moscow’s terms for a deal in eastern Ukraine, which would require admitting figures from the Russian-backed separatist movement to Ukraine’s parliament.
Or it could herald a broader intervention: Russian airstrikes, amphibious landings, or a tank assault across the border with Belarus, a Russian ally.
In the Ukrainian position on this section of the eastern front, the surrounding landscape is open, snowy steppe. Soldiers guard infantry or tanks. In the open fields, a chill wind stirred dry grass and cloud shadows played across the empty plains.
All was quiet on a recent visit by Ukrainian and foreign reporters. One sergeant, also giving only his first name, Nikolai, said he was ready to fight no matter how the conflict started.
But he hoped not to. “A more active phase of the war means more deaths,” he said. “More parents without children, more children without parents. We really don’t want Russia to invade.”
The author is a journalist for The New York Times
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