Russia will celebrate the 80th anniversary of Nazi Germany’s defeat on Friday with visiting heads of state and a show of armed might in Red Square, staged as a display of global clout, grandiose and intimidating, and a portent of eventual triumph in the war against Ukraine.

The annual military parade below the walls and towers of the Kremlin is expected to be the largest since Russia invaded Ukraine in 2022, a commemoration the government and its cheerleaders have used to raise support for the war, conflating what may be the greatest source of national pride with the far more divisive current conflict.

“Our great victory 80 years ago is a new narrative, new conception of Russia’s current standoff with the West,” Sergei Lyaguzin, an international relations professor, said on Russian state television this week.

Behind the pomp, though, Russia stands on shakier ground than the Kremlin’s confident show suggests. Its military is barely advancing on the battlefield, its economy is sputtering, prices for oil, its main export, are falling and, perhaps most surprising, President Trump is hinting that his view of President Vladimir V. Putin and his war is souring.

Mr. Putin has played down these challenges, accepting short-term economic pain and diplomatic setbacks in the hope that his persistence will eventually yield a triumph of historic proportions, said Alexander Kolyandr, a Russian economy expert at the Center for European Policy Analysis, a research group.

“They are convinced that they are more resilient than their opponents,” he said in a phone interview. “They believe that victory will not go to the side that is the best, but to the one that remains standing the longest.”