The reason for impeachment

This is from an article entitled "If Beale Street Could Talk – Part 2" by David Swanson:

If we go into the next presidency with the next president free to launch wars on the basis of lies, torture, murder, detain without charge, spy without warrant, rewrite laws with signing statements, hide the workings of our government, disobey laws on his or her whim . . . I don't care what party he or she is from, I don't care if it's Nelson Mandela, you don't give that power to a human being. And that's what we're doing if we fail to impeach Bush and Cheney.

I think that is a terribly important point. Why doesn't Nancy Pelosi get it?