In what will probably come as a surprise to many Americans, the U.S. Constitution doesn't explicitly guarantee a right to vote. That lamentable absence has sparked a movement of sorts, with commentators calling for the adoption of such an amendment to combat a wave of vote-suppression tactics that have been implemented by conservative state legislatures across the country. But while a right-to-vote amendment would certainly be welcome, it probably won't do all that much to protect the vote.

Vox's Matt Yglesias, for one, makes a compelling case for a right-to-vote amendment, taking into account not only the anti-democratic laws being passed at the state level, but also the Supreme Court's refusal to do anything about them. This is despite the fact that the Constitution does contain various provisions preventing the franchise from being restricted, such as the Fifteenth Amendment, which mandates that 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."

Even in its worst periods, the Supreme Court did not uphold state laws that explicitly excluded African-Americans from the franchise (whether directly or through "grandfather clauses" that barred African-Americans from voting). But the court did uphold state restrictions, such as literacy tests and poll taxes, that were written in race-neutral language — even though they had the same effect and intent as outright disenfranchisement.

To deal with these kinds of evasions, Yglesias endorses the constitutional amendment proposed by Reps. Keith Ellison (D-Minn.) and Mark Pocan (D-Wisc.), which would codify the principle that "every citizen of the United States, who is of legal voting age, shall have the fundamental right to vote in any public election held in the jurisdiction in which the citizen resides."

However, while this is a laudable amendment, it's worth considering some of the limitations of this strategy.

As Yglesias acknowledges, the first issue is that Article V makes amending the Constitution enormously difficult. The Constitution has been amended only 17 times since 1789, and many of these have been minor. Granted, outside the unusual Civil War amendments, access to the ballot is the one substantive right that has been added post–Bill of Rights through formal amendment. In addition to the Fifteenth Amendment, the Nineteenth (extending the franchise to women), the Twenty-Third (giving electoral votes to the District of Columbia), the Twenty-Fourth (banning poll taxes), and the Twenty-Sixth (giving the right to vote to 18-year-olds) Amendments all enfranchised voters through the amendment process.

Still, in the current political climate it's impossible to see the Ellison/Pocan amendment winning supermajorities in Congress or the support of three-fourths of the states. Most Republican legislators would understand perfectly well that the proposed amendment is squarely pointed at the vote-suppression tactics that have become increasingly crucial to the dwindling GOP coalition.

And even if an amendment did pass, it's not at all clear that the problem would be solved.

The limitations of using the Constitution to protect the right to vote can be summed up in two words: Shelby County. Section 2 of the Fifteenth Amendment explicitly empowers Congress "to enforce this article by appropriate legislation." Nonetheless, in 2013 the Supreme Court gutted the 1965 Voting Rights Act, even though Chief Justice John Roberts' opinion was not backed by any constitutional provision suggesting a restriction on Congress' Fifteenth Amendment powers, nor any precedent not authored by Roberts himself. As Judge Richard Posner observed in Slate, "The opinion rests on air."

The framers of the Reconstruction amendments would not have been surprised by Shelby County. As the University of Maryland's Mark Graber demonstrated in an extraordinary new paper, with the exception of Rep. John Bingham, the framers of the Fourteenth Amendment paid relatively little attention to the precise wording of the substantive rights in Section 1. Their skepticism about what James Madison called "parchment rights" was strongly influenced by the Supreme Court's infamous 1857 Dred Scott decision, which ruled that Congress had no power to ban slavery in federal territories — despite explicit textual language giving Congress the power to "make all needful Rules and Regulations" concerning the territories. (As it happens, both Dred Scott and Shelby County relied on the dubious theory that the explicit powers of Congress should be limited by a "equal sovereignty of the states" principle, a principle wholly created by the judiciary.)

For this reason, they were more concerned about preserving the ability of Republicans to control the federal judiciary than with exactly what words the Constitution should use to protect the rights of freed slaves.

In other words, they thought that bad judges were a much bigger problem than textual lacunae, and there's a great deal of truth in this. It's very likely that the Roberts Court would uphold most contemporary vote-suppression laws even if a right-to-vote amendment was passed.

Moreover, in all likelihood these vote-suppression techniques already violate the existing text of the Constitution. A federal district judge, for example, found that Texas' draconian voter ID law was racially discriminatory in both effect and purpose, and also functions as a poll tax. If these findings are accurate, the Texas law already violates the Fourteenth, Fifteenth, and Twenty-Fourth Amendments.

None of this is to deny that changes in textual language could matter at the margin. I can imagine certain judges, particularly moderate Democratic nominees, who would uphold voter ID requirements under the current constitution, but not under an amended one. However, the track record of textual protections for the right to vote is generally poor.

The courts, in other words, are unlikely to protect the right to vote unless the principle has substantial political support. And that, in the end, may be the best reason to mobilize a constitutional right to vote, despite its limitations. A new amendment may not do much in theory — but if a movement can increase popular support for the right to vote, it's worth it in itself.