For the first time since the second world war, Russia has been invaded.
On the previous occasion the Red Army’s Ukrainian troops helped beat back the Nazi assault in Russia’s Kursk province.
Now it is Ukrainians who are advancing over the same ground. Ukraine’s surprise attack, which began on Aug. 6, is bold and daring, and could change the narrative of the war.
It is also a gamble which could go badly wrong.
Morally and legally, Ukraine has every right to take the fight into Russia. Every state is entitled to defend itself, and that right does not stop at the border.
Russia is waging an unprovoked war of conquest in Ukraine, and has conducted thousands of attacks on Ukraine’s Sumy region from over the frontier in Kursk. The troops, kit and bases that enable those attacks are legitimate targets.
Ukraine’s Kursk offensive has already achieved some successes. Its forces have cut through the region, occupying scores of settlements and taking hundreds of prisoners.
That has had three immediate effects.
One is to boost morale at home, which needed a jolt: Ukraine’s army is on the back foot in the Donbas region and its counter-offensive last year fizzled out.
The second is to show international partners that Ukraine can regain the initiative. Encouragingly, America and Germany, among others, have indicated that they are comfortable with their weapons being used on Russian soil.
The third is to expose Russia’s vulnerabilities.
Vladimir Putin will use the incursion to reinforce his big lie that Russia is waging a defensive war against the West.
But it also adds to the evidence that Mr. Putin’s carefully constructed image of strength and control is hollow.
He thought he could conquer Ukraine in a few days in 2022, but two years later he still hasn’t. When his former chef led a mutinous march much of the way to Moscow last year, Russian troops stood aside.
When Ukraine invaded Kursk, local civilians did not resist.
