George W. Bush is the reason the Founders put impeachment in the Constitution

"The Case for Impeachment" by Scott Horton

[F]ailure to use impeachment has its consequences: it means acceptance of Bush’s transformation of the constitutional order. It means that the careful balance between legislature, executive and judiciary created by the Framers has been undone, and the executive has triumphed as the paramount power. Impeachment may be a painful process, of course, but Americans should consider whether their Constitution is worth saving.