"Chuck Colson arrived at the minimum-security federal prison on the grounds of Maxwell Air Base in Montgomery, Ala., via the White House, where he had been not just a member but a leader of the Nixon administration and gang. He'd been convicted, as Richard Nixon should have been, of obstruction of justice.
No doubt about it, Chuck Colson could obstruct with the best of them, or rather the worst. That connoisseur-in-chief of dirty tricks, Richard Mountebank Nixon himself, gave him the highest recommendation in his presidential memoirs:
Mr. Colson, the former president wrote, was his "political point man" for "imaginative dirty tricks"
Just what is meant by 'dirty tricks' ? Do all Presidents use them? Name some.