Was the Enforcement Act of 1870 a valid exercise of Congress's power to enforce the Fifteenth
Amendment?

No. In an 8-1 decision authored by Chief Justice Morrison Waite, the Court concluded that the relevant sections of the Enforcement Act lacked the necessary, limiting language to qualify as enforcement of the Fifteenth Amendment. The Chief Justice first stated that the Fifteenth Amendment "does not confer the right of suffrage upon any one," but "prevents the States, or the United States, however, from giving preference…to one citizen of the United States over another on account of race, color, or previous condition of servitude." In examining the language of the Enforcement Act, the Court noted that, while the first two sections of the act explicitly referred to race in criminalizing interference with the right to vote, the relevant third and fourth sections refer only to the "aforesaid" offense. According to the Court, this language does not sufficiently tailor the law to qualify as "appropriate legislation" under the Enforcement Clause of the Fifteenth Amendment.

Explanation:

i believe it is the second one.   if correct plz mark brainliest.