Chapter VI: Section 4: of Article I of the Constitution declares

The times, places, and manner of holding elections for
Senators and Representatives shall be prescribed in each State
by the legislature thereof; but the Congress may at any time,
by law, make or alter such regulations, except as to the
places of choosing Senators.

The fifteenth amendment of the Constitution is as follows:

SEC. 1. The right of citizens of the United States to vote
shall not be denied or abridged by the United States or by
any State on account of race, color, or previous condition of
servitude.

SEC. 2. The Congress shall have power to enforce this article
by appropriate legislation.

The Supreme Court has held that this amendment invests the citizens of the United States with a new constitutional right which is within the protecting power of Congress. That right the court declares to be exemption from discrimination in the exercise of the elective franchise on account of race, color, or previous condition of servitude. The power of Congress to protect this right by appropriate legislation is expressly affirmed by the court.

National legislation to provide safeguards for free and honest elections is necessary, as experience has shown, not only to secure the right to vote to the enfranchised race at the South, but also to prevent fraudulent voting in the large cities of the North. Congress has therefore exercised the power conferred by the Constitution, and has enacted certain laws to prevent discriminations on account of race, color, or previous condition of servitude, and to punish fraud, violence, and intimidation at Federal elections. Attention is called to the following sections of the Revised Statutes of the United States, viz: