In the chapters which have gone before, the powers of Congress have been considered. In connection therewith have been discussed the express and implied limitations which restrain Congress in the exercise of those powers, as, for example, with reference to the subject of taxation, the express limitation that all taxes, other than direct, shall be uniform throughout the United States, and the implied limitation, that the salaries of state officials, or the evidences of state indebtedness shall not be federally taxed.

In the present chapter we shall have to deal with the general limitations laid by the Constitution upon Congress, either by way of the absolute denial to Congress of a power, or by way of provision that the power shall be exercised only under certain specified circumstances.

It would seem that certain of these limitations thus expressly imposed operate as an absolute denial to Congress of a legislative power with reference to the subjects specified, without regard to time or place. Others of these limitations, as was held in the Insular Cases, serve to restrain the legislative powers of Congress only when dealing with the States and incorporated territories.1

1 "There is a clear distinction between such prohibitions as go to the very root of the power of Congress to act at all, irrespective of time and place, and such as are operative only 'throughout the United States' or among the several States. Thus, when the Constitution declares that 'no bill of attainder or ex post faclo law shall be passed,' and that 'no title of nobility shall be granted by the United States' it goes to the competency of Congress to pass a bill of that description. Perhaps the same remark may be applied to the First Amendment that 'Congress shall make no law respecting an establishment of religion, or prohibiting the free exercise thereof; or abridging the freedom of speech; or of the press; or the right of the people to peacefully assemble and to petition the government for a redress of grievances.' We do not wish, however, to be understood as expressing an opinion how far the bill of rights contained in the first eight Amendments is of general and how far