Ukraine is democracy's frontline and a moment of truth for the world

The frightful noise of gunfire, bombing and children's screams in the cities of Ukraine reverberates across Europe.

The full-scale Russian invasion is an unprovoked, heinous crime perpetrated against Ukraine's citizens, their sovereign democratic state and all the free peoples of the world. The 24th of February is a day that will live in infamy. It will not be forgiven. It will surely never be forgotten.

Last weekend it appeared Russia had failed to gain the swift victory it expected. Fierce street fighting in Kyiv and other cities spoke to the bravery of the country's soldiers and ordinary Ukrainians determined to defend their land. But if a thwarted Kremlin orders its forces to step up attacks, a bloodbath of Ukraine's citizen fighters could ensue.

At this moment of maximum danger, it's imperative that Vladimir Putin, Russia's president and sole architect of this needless calamity, implements an immediate ceasefire. Militarily, he has miscalculated. Diplomatically, he is isolated, as the UN security council's condemnation of Moscow's actions shows. Even his ally, China, refused to support this vile aggression. Politically, at home, Putin's war is provoking widespread protests and unrest.

Now is a time for cool heads and wise counsel in western capitals. The longer the fighting continues, the higher will be the number of people killed and maimed, the wider the political gulf and the greater the prospect that this conflict may spill into Poland and other nearby countries. As Nato reinforces its eastern flank and tensions rise across the board, the risk of confrontation between Russia and the western alliance grows.