[henderson field]

He's a public figure.
He can't be libeled.
Everything bad about him is true.
Now is the time to deport him.

[Tunehead54]

He's a public figure. He can't be libeled.

---

While truth is a complete defense - even public figures can sue and win libel judgments when there is "actual malice", known falsity and something else (NYTimes vs Sullivan).

Having said that I think you're pretty safe calling Kerry a low-down, lying sack of cow excrement and rely on the truth defense to keep safe from a libel judgment. ;-)