In a speech on Wednesday, President Vladimir V. Putin said that he would require hundreds of thousands more Russians to fight in Ukraine — and alarmed the West by once again raising the specter of nuclear force.The mobilization signals that Mr. Putin is turning the war from one of aggression to one of defense, offering clues about what the next phase of the fighting will involve.Guest: Anton Troianovski, the Moscow bureau chief for The New York Times.Background reading: Accelerating his war effort, Mr. Putin accused the West of trying to “weaken, divide and ultimately destroy” Russia.American and other officials vowed to continue sending military, economic and humanitarian aid to Ukraine.For more information on today’s episode, visit nytimes.com/thedaily. Transcripts of each episode will be made available by the next workday.