The Constitution is not a suicide pact.

The US has placed Anwar Awlaki on a kill or capture list. His father is sueing to have him removed from it. Obama's people will probably use a variation of the title in their arguments in court.
The expression "suicide pact" was first used by Justice Robert H. Jackson in a dissent in Terminiello v. Chicago, in 1949.
The sentiment had been expressed earlier but not that concisely.
Thomas Jefferson: Changed his mind about how much power the Federal Government had when he got the chance to make the Louisiana Purchase. In justifying his actions, he later wrote: "[a] strict observance of the written law is doubtless one of the high duties of a good citizen, but it is not the highest. The laws of necessity, of self-preservation, of saving our country when in danger, are of higher obligation. To lose our country by a scrupulous adherence to the written law, would be to lose the law itself, with life, liberty, property and all those who are enjoying them with us; thus absurdly sacrificing the ends to the means."[1]
Abraham Lincoln: Suspended habeas corpus (a congressional power) as a wartime measure to maintain order and when criticized he responded: “ … Are all the laws, but one, to go unexecuted, and the government itself go to pieces, lest that one be violated?"
Later in the war, after being criticized for the arrest and detention of Congressman Clement Vallandigham of Ohio, Lincoln wrote that he was arrested "because he was laboring, with some effect, to prevent the raising of troops, to encourage desertions from the army,. . . Must I shoot a simple-minded deserter, while I must not touch a hair of a wily agitator who induces him to desert?"