Vladimir Putin was looking for a swift invasion that would halt Ukraine’s drift toward the West, reveal NATO’s fractures and weaknesses and solidify Russia as a global power. In response, the West threatened moderate sanctions, but ultimately showed little interest in stepping between Russia and Ukraine.Then came the war, and everything changed. Russia’s invasion met with valiant Ukrainian resistance. President Volodymyr Zelensky became an international hero. NATO countries unified behind a truly punishing sanctions regime and significant military support. Russia’s attack strengthened Ukraine’s national identity — and its desire to join the European Union. A conflict that the U.S. and Europe were treating as purely strategic is now a conflict about the West’s most fundamental values.Much of this has felt hopeful, even inspiring, to those watching from the comfort of home. But it has the potential to unleash a truly terrifying spiral of escalation. Putin, feeling backed into a corner, has raised the stakes. Last week, he called the West’s sanctions akin to an act of war and has put Russia’s nuclear arsenal on alert. And the global wave of support for Ukraine has made it increasingly difficult for Western leaders to de-escalate. In the fog of war, it isn’t hard to imagine an accident or miscommunication that triggers a World War III-like scenario.So what does a settlement here look like? What does Putin want? What would Zelensky accept? What will Europe and the U.S. sign onto? Is there any deal that could work for all the players?There are few people better positioned to answer those questions than Fiona Hill. Hill is a senior fellow in the Center on the United States and Europe at the Brookings Institution. She served as deputy assistant to the president and senior director for European and Russian affairs on the National Security Council under Donald Trump and as a national intelligence officer for Russia and Eurasian affairs under Barack Obama and George W. Bush. And she is the co-author of the influential Putin biography “Mr. Putin: Operative in the Kremlin.”We discuss how Putin’s motivations and ambitions have changed dramatically in the last decade, why Ukrainian identity is absolutely central to understanding this conflict, whether NATO expansionism is responsible for the current conflict, the different pathways the war could take, how political incentives have created a spiral of escalation for Russia, Ukraine and the West, whether the economic pain of the sanctions can incentivize regime change in Moscow, the possibility of China playing a mediating role in resolving the conflict, the dangers of backing Putin into a corner, whether Putin is willing to use nuclear weapons, what de-escalation could look like at this point, and much more.Book recommendations: Bloodlands by Timothy SnyderNot One Inch by M.E. SarotteThe Limits of Partnership by Angela StentPutin’s World by Angela StentRussia Under the Old Regime by Richard PipesThe Formation of the Soviet Union by Richard PipesThoughts? Guest suggestions? Email us at ezrakleinshow@nytimes.com.You can find transcripts (posted midday) and more episodes of “The Ezra Klein Show” at nytimes.com/ezra-klein-podcast, and you can find Ezra on Twitter @ezraklein. Book recommendations from all our guests are listed at https://www.nytimes.com/article/ezra-klein-show-book-recs.“The Ezra Klein Show” is produced by Annie Galvin, Jeff Geld and Rogé Karma; fact-checking by Michelle Harris; original music by Isaac Jones; mixing by Jeff Geld; audience strategy by Shannon Busta. Our executive producer is Irene Noguchi. Special thanks to Kristin Lin and Kristina Samulewski.