When the order to cross the
frontier came from the Kremlin, eight years of Russian military activity
on Ukraine's eastern borders came to a crescendo.
President Vladimir Putin has officially recognised
the independence of two breakaway regions
and sent his so-called peacekeeping forces in.
Their target?
The Moscow-backed rebel regions of Donetsk and Luhansk.
The two oblasts which make up the Donbass have been in the grips
of a brutal war between Ukraine's eastern forces
and Russian separatists.
The conflict started in 2014
and has since claimed 14,000 lives.
Conflict erupted in February of that year,
Ukrainian protesters drove their Moscow-friendly president from office
in what became to be known the Revolution
of Dignity.
Russia responded by annexing
Ukraine's long-contested Crimean peninsula, which along with the rest of Ukraine,
had been part of the Soviet Union until it collapsed in 1991.
The Kremlin has also sought finance and fuel
during the conflict in the mostly Russian-speaking east.
By April,
Moscow-backed rebels had begun seizing government buildings
in Donetsk and Luhansk.
They also set fire to those in Ukraine's
second city, Kharkov.
In May, the regions held a popular vote
to declare independence and make a bid to join Russia.
Ukraine and the West accused Russia of backing
the rebels with troops and weapons.
But Moscow denied the allegations.
Then, in July, amid heavy warfare,
a Malaysian Airlines flight was shot down over
eastern Ukraine.
All 298 people aboard were killed.
An international investigation found that
the plane was brought down by a Russian-supplied missile
and that it was sent from the rebel-controlled region.
Moscow still denies any involvement.
Then, in August, a peace agreement was reached
after a major defeat of Ukrainian troops.
Known as the first of two Minsk agreements,
the deal promised that the separatist regions could have a degree of autonomy.
But it quickly collapsed and the large scale
fighting resumed.
This led to another major defeat
of Ukrainian forces at Debaltseve in January
and February of 2015.
In February of the same year,
the second Minsk agreement was signed.
It required Ukraine to grant special status to the separatist regions,
allowing them to create their own police force and have a say
in appointing local prosecutors and judges.
The peace deal helped end full scale fighting,
but the situation remained tense.
The frozen conflict has drained Kiev's resources
and effectively put a stop to its goal of joining NATO.
But now, with his
recognition of these two regions as independent,
Putin has violated the Minsk agreements,
which specifically outlawed it.
It's a move
that Russia has never made before.
And the announcement came on the same day that President Biden and Putin
agreed to a possible summit over Ukraine.
Biden and other Western leaders have responded with immediate sanctions.
But, will these be enough to force Russia to change course?
To make them effective, the West would have to be in it for the long haul.
And, as Ukraine rapidly turns into a battleground,
time is not a luxury Kyiv can afford.