Ending the war in Ukraine very much depends on how and when President Vladimir V. Putin of Russia allows it to end. In an interview for his podcast “The Ezra Klein Show,” the opinion columnist Ezra Klein spoke with one of the world’s leading experts on Mr. Putin, Fiona Hill, a foreign policy adviser for three United States presidents. Today, we run the discussion between Ms. Hill and Ezra Klein about how Mr. Putin is approaching this moment, and the right and wrong ways for the West to engage him. Guest: Fiona Hill, a senior fellow at the Center on the United States and Europe at the Brookings Institution.