One of the great unwritten rules of modern political life is that former presidents do not publicly criticize the policies of a sitting successor.
So when a man regarded as one of the most gentlemanly of former presidents breaks that rule, members of both parties should take notice. Former President Jimmy Carter has aggressively criticized President Bush in his self-described "first" political book, Our Endangered Values: America's Moral Crisis.
The book reveals a different Jimmy Carter than the pleasant, conciliatory soul the nation has come to know since he left office in 1981. There's outrage and disgust for what he sees as the sins of the Bush White House.
He attacks Mr. Bush's "arrogance," and as a Christian, Mr. Carter insists Mr. Bush is using his "fundamentalism" to take the nation on a path it doesn't want to go. The former president maintains that unyielding partisanship has overcome civility in government, and that deficit spending is out of control.
Mr. Carter also expresses anger and distress about the nation's policies abroad.
The invasion of nations that don't pose a direct threat to America is lamentable, he believes, as are long-term peace agreements that have effectively been dismissed.
The White House has abandoned human-rights agreements while graying the lines between church and state, and it worries him that Americans' civil liberties are being restricted, that the administration might have secret prisons abroad, and that it opposes a congressional ban on torture of foreign prisoners.
"I never dreamed we'd ever even consider that," he said. "I have been reluctant to criticize this President. But this President has radically departed from [the policies] of all previous presidents."
Harsh words indeed from one member of the club to another.
Mr. Carter certainly knows something about low job approval ratings. His lowest rating as president was 28 percent, worse than Mr. Bush's.
But perhaps because he knows what the roller-coaster ride is like, Jimmy Carter's insights into the effect of President Bush's policies, at home and abroad, should worry every American.