The following is the second in a series of guest posts by Travis Crum on the 150th anniversary of the 15th amendment:

In celebrating the Fifteenth Amendment’s sesquicentennial, let’s start at the beginning and ask a deceptively complicated question: Why did Congress pass the Fifteenth Amendment instead of the Voting Rights Act of 1869?

By the time the Fifteenth Amendment was sent to the States for ratification in early 1869, Congress had already passed legislation enfranchising black men in the District of Columbia, the federal territories, and the Reconstructed South. Blacks, however, remained disenfranchised in several Northern and Border States. Given our current understanding of the Fourteenth Amendment—which had just been ratified—Congress would have been well within its constitutional authority to mandate black suffrage in the States.

One possible explanation is that the Fifteenth Amendment was an entrenchment device. But this narrative only explains why there is an amendment; it does not explain why the Reconstruction Congress did not first pass a Voting Rights Act of 1869.

As I detail in my forthcoming law review article, The Superfluous Fifteenth Amendment?, the Reconstruction Congress actively considered passing both a nationwide suffrage statute anda constitutional amendment. The Radical Republicans’ logic was straightforward: ratification of the Fifteenth Amendment was by no means assured and a statute enfranchising black men in the Border States and the North would create a powerful new voting bloc in support of ratification.

Congress, however, rejected the statutory solution and opted for only an amendment. Moderate Republicans—who were the swing voters at the time—believed that Congress lacked enforcement authority under the then-recently ratified Fourteenth Amendment to impose voting qualifications on the States and that an amendment was the only legally and politically viable option. This logic may seem alien today, but the Reconstruction generation conceptualized civil and political rights as distinct bundles. Under this view, citizenship was not coextensive with suffrage, and the Fourteenth Amendment’s protections did not include the franchise. Hence, the Reconstruction generation’s belief that the Fourteenth Amendment did not enfranchise women and the necessity of the Nineteenth Amendment, which coincidentally turns 100 this year.

Congress’s actions here follow a pattern. Throughout the Civil War and Reconstruction, racial progress proceeded in an incremental fashion. The Emancipation Proclamation—which freed slaves in the Confederacy but not in the four Border States—was the forerunner to the Thirteenth Amendment. The Civil Rights Act of 1866 was the statutory precursor to the Fourteenth Amendment. In each of these examples, a sub-constitutional rule was later expanded on and entrenched via a constitutional amendment.

So too with the Fifteenth Amendment. The Thirty-Ninth Congress dramatically expanded black suffrage in areas of federal control, but it drew the line at enfranchising blacks in States. After the Fourteenth Amendment was ratified, the Fortieth Congress respected those lines, rejected the nationwide suffrage statute proposed by the Radicals, and pushed through a constitutional amendment. The Fifteenth Amendment, therefore, was a new grant of federal authority, distinct from Congress’s Fourteenth Amendment power and meriting a distinctive doctrinal framework.

Ultimately, the Reconstruction Framers’ decision to pursue a constitutional amendment proved fortuitous. In the 1870s and 1880s, the Supreme Court invalidated or severely curtailed laws that enforced the Fourteenth Amendment, including the Civil Rights Act of 1875’s prohibition on racial discrimination in public accommodations. And in 1894, Congress repealed several Reconstruction-era laws that protected the right to vote. It is not difficult to imagine a similar fate befalling a Voting Rights Act of 1869 if passage of that statute had backfired politically and doomed the Fifteenth Amendment’s ratification. By enshrining the right to vote free of racial discrimination into the Constitution, the Reconstruction Framers preserved a powerful legal and rhetorical tool that would prove immensely valuable during the Civil Rights Movement.