Biden's bold move

Nevertheless, the man whom Donald Trump contemptuously nicknamed "Sleepy Joe" showed once again that he is up to the seriousness of the international situation. And this can obviously do him no harm as he weighs up running for a second term.

He went to the capital of a country at war while his Russian counterpart still hasn't set foot on the front line.

Joe Biden also stole some of Vladimir Putin's thunder, and from the Russian president's much-awaited state of the nation speech Tuesday, on the eve of the war's anniversary. But above all, he went to the capital of a country at war while his Russian counterpart still hasn't set foot on the front line with his own soldiers.

Biden's visit gives weight to Putin's argument that the war in Ukraine is a direct confrontation between Russia and the entire West. This is an argument Russia has used both at home and to stir up anti-Western sentiment in non-Western countries.

A boost for American leadership

But that's not what matters the most: The message Biden is sending to Putin is that he should not count on any kind of "fatigue" from the United States — and he has proven that by announcing an additional $500 million in military aid. In Munich this weekend, U.S. members of Congress, Democrats and Republicans alike, came to deliver the same message to Europeans who may be wondering about Western commitment.

Vladimir Putin relied on a weak reaction from the West. He was clearly mistaken.

At every stage of the conflict, each side makes its decisions based both on what it perceives as the other's intentions, and also on the other's determination. Last year, when he decided to launch the invasion of Ukraine, Vladimir Putin relied on a weak reaction from the West — a few sanctions, maybe, but certainly not the massive support we have seen for the past year. He was clearly mistaken.

Today, Ukraine's allies want Moscow to understand how determined they are to oppose a Russian victory. This will not prevent future military offensives, but at least the Kremlin knows it cannot hope for long-term Western demobilization.

The significance of this trip is also strong in Europe, mainly in the ex-communist countries, who have unlimited faith in American leadership and NATO, but less so in the idea of a Europe under construction. Joe Biden gave them a new reason to believe in that leadership unreservedly yesterday.