The privileges of the writ of habeas corpus shall not be suspended, unless when in cases of rebellion or invasion the public safety may require it.
"It has been judicially decided that the right to suspend the privilege of the writ rests in congress, but that congress may by act give the power to the president." [Footnote: Lalor's Cyclopedia of Political Economy]
The privilege of the writ never was suspended by the general government until 1861. Questionable suspensions of the writ, covering a very limited territory, had been made in two or three instances by generals.
So valuable as a "bulwark of liberty" is this writ considered to be, that the courts of the United States have decided that, even in time of war, the privilege of the writ can be suspended only in that part of the country actually invaded, or in such a state of war as to obstruct the action of the federal courts.
Clause 3.—Certain Laws Forbidden.
No bill of attainder[1] or ex post facto law[2] shall be passed.
[1] A bill of attainder was a legislative conviction for alleged crime, with judgment of death. Those legislative convictions which imposed punishments less than that of death were called bills of pains and penalties. [Footnote: Cooley's Constitutional Limitations] The term is here used in its generic sense, so as to include bills of pains and penalties.
The great objection to bills of attainder is that they are purely judicial acts performed by a legislative body. A legislative body may and should try a political offense, and render a verdict as to the worthiness of the accused to hold public office. But to try him when conviction would deprive him of any of his personal rights—life, liberty, or property,—should be the work of a duly organized judicial body.
This provision, then is directed not so much against the penalty (for limitations upon penalties are found elsewhere in the constitution,) as against the mode of trial. Or we may say that it is intended to prevent conviction without a trial; for in previous times legislative bodies had frequently punished political enemies without even the form of a trial, or without giving them an opportunity to be heard in their own defense, by passing against them bills of attainder.
[2] An ex post facto law is, literally, one which acts back upon a deed previously performed. But as here intended, it means a law making worse such an act, either by declaring criminal that which was not so regarded in law when committed, or by increasing the penalty and applying it to the act previously performed.