Matt Yglesias talks about One Billion Americans, his book arguing that it’s in the United States’ national interest to dramatically boost its population, by expanding immigration and having more babies.

Matt and Julia also discuss arguments for and against the “YIMBY” movement, which pushes for building more housing; what they’ve both learned from reflecting on their misguided support for the Iraq War in 2003; and why (and how) Matt is trying to be more of a rationalist.