It’s been remarkable watching the Democratic Party act like a political party this past month — a party that makes decisions collectively, that does hard things because it wants to win, that is more than the vehicle for a single person’s ambitions. But parties are made of people. And in the weeks leading up to President Biden’s decision to drop out of the race, it felt like the Democratic Party was made of one particular person: Nancy Pelosi. Two days after Biden released a forceful letter to congressional Democrats insisting he was staying in the race, the former speaker went on “Morning Joe” and cracked that door back open. And Pelosi has pulled maneuvers like this over and over again in her political career. When an opportunity seems almost lost, she simply asserts that it isn’t and then somehow makes that true. Sometimes it seems like Pelosi is one of the last people left in American politics who knows how to wield power. Pelosi has a new book, “The Art of Power: My Story as America’s First Woman Speaker of the House,” and I wanted to talk to her about her role in Biden’s decision to drop out and what she’s learned about power in her decades in Congress.