What is Victory Day in Russia, and why is it so significant?

Victory Day, celebrating the Soviet Union’s vanquishing of Nazi Germany in 1945, is Russia’s most important secular holiday, although it is toned down this year as the war in Ukraine drags on.

More than 20 cities, some thousands of miles from the battle lines, said they would forgo military parades, and organizers canceled a popular nationwide march honoring veterans.

Here’s a look at the significance the holiday has taken on during President Vladimir V. Putin’s two decades in power.

Why does Victory Day matter so much?

Mr. Putin has helped transform Victory Day — meant to honor the 27 million Soviets who died in World War II — into one of the most important holidays on the Russian calendar, a nostalgic ritual that buttresses national pride and unifies a sometimes divided society.

Mr. Putin has long used his Victory Day speech to disparage the West and forge unity around Russian military power. Last year, weeks after invading Ukraine, he did not explicitly warn of an existential battle with the West — a theme he revived a few months later — but sought to reassure the Russian people that their lives would go on as normal.

This year, the holiday is taking place at a critical juncture of the war, amid mounting anxiety after a series of attacks inside Russia’s borders and with fighting intensifying in advance of an expected Ukrainian counteroffensive.

What happens on Victory Day?

The country’s biggest parade, which takes place outside the Kremlin on Red Square, is usually a display of raw military might, with row upon row of carefully choreographed soldiers marching amid weapons ranging from vintage tanks to intercontinental ballistic missiles. But this year, there was only one old Soviet tank in the procession, and no modern ones.

Many local parades were canceled, and perhaps the most striking change was the decision to call off the nationwide Immortal Regiment march, in which ordinary Russian citizens take to the streets to display pictures of their veteran forebears.

Some analysts have suggested that the Kremlin might be nervous about putting crowds of Russians on the streets at such an uneasy time, even with Russia’s draconian wartime laws against protests.

Analysts said that Russian officials could have been worried that thousands of people would show up with pictures of those newly killed in the war, revealing the extent of a toll that the government has tried to conceal.

How has Mr. Putin tied Russia’s victory over the Nazis to Ukraine?

The Kremlin has cast the war as a continuation of Russia’s fight against evil in World War II, which is known in the country as the Great Patriotic War, and on Tuesday Mr. Putin directly made that connection again, portraying the invasion of Ukraine as a “sacred” struggle for the survival of the Russian state.

In the past, Mr. Putin has variously called Ukraine’s government “openly neo-Nazi,” “pro-Nazi” and controlled by “little Nazis.” The sudden emergence of allegations of Nazism shows how Mr. Putin is trying to use stereotypes, distorted reality and his country’s lingering World War II trauma to justify the invasion.

That language has been a persistent element of Russian messaging, even though Ukraine is led by a president, Volodymyr Zelensky, who is Jewish, and last fall enacted a law intended to combat antisemitism.