•Set: The*!Tpowers are to be so construed ns to effect the object they are dcs gned to ac sjonrplteh. It Is the doty ef the Courtto a* certain this, and then determine whether the legislation will defeat or secure the end. A restriction to the class of powers is that Con sressfthsll pass no erpost facto law or bill of attainder. The meaning of this is well un derstood to be any law which makes an act a