If all those liberals who regret their support for the Iraq war seriously want to atone for it, there is something they could do. They could start exposing the lies about Iran. For the last 10 years we have been told that Iran is 2 years away from having a nuclear weapon.
If Matt Yglesias, Ezra Klein, Joshua Micah Marshall, Kevin Drum, and all the other liberal hawks were to start systematically exposing the lies about Iran it might, just might, make a difference. They owe it to all the Iranians and all the members of the armed forces whose lives are placed at risk by these lies.