WARSAW — President Biden delivered a forceful denunciation of Vladimir V. Putin’s invasion of Ukraine on Saturday, declaring “for God’s sake, this man cannot remain in power,” as he cast the war as the latest front in a decades-long battle between the forces of democracy and oppression.
Ending a three-day diplomatic trip to Europe with a fiery speech outside a centuries-old castle in Warsaw, Mr. Biden described the Russian invasion of Ukraine as the “test of all time” in a post-World War II struggle between democracy and autocracy, “between liberty and repression, between a rules-based order and one governed by brute force.”
“In this battle, we need to be cleareyed,” Mr. Biden said in front of a crowd waving Polish, Ukrainian and American flags. “This battle will not be won in days or months, either. We need to steel ourselves for the long fight ahead.”
Mr. Biden used the speech to bolster a key NATO ally on Ukraine’s western border that has served as a conduit for Western arms and has absorbed more than 2 million refugees fleeing the violence, more than any other country in Europe. And he sought to prepare the public, at home and abroad, for a grinding conflict that could drag on for weeks, months or longer.
Just hours before the event, missiles struck the western Ukrainian city of Lviv, about 50 miles from the Polish border, extending Russia’s monthlong assault on major cities and civilian populations — and undercutting Russian statements a day earlier suggesting Moscow might be scaling back its goals in the war.
While declaring that “the Russian people are not our enemy,” Mr. Biden unleashed an angry tirade against Mr. Putin’s claim that the invasion of Ukraine was intended to “de-Nazify” the country. Mr. Biden called that justification “a lie,” noting that President Volodymyr Zelensky of Ukraine is Jewish…