Puck/Library of Congress

There are a lot of reasons that I love the Seventeenth Amendment, which transferred the power to elect senators from state legislatures to ordinary voters.

Its passage was one of the most sweeping progressive victories in American history—public fury so intimidated reactionary lawmakers in the Senate that, by approving the Amendment, they in effect voted their own body out of existence.

A second reason is that in the past two decades, new redistricting techniques have allowed state legislatures to create unshakably safe House districts for their members. (Because Republicans controlled a majority of legislatures after the 2010 census, most Republican seats are as safe as Brezhnev's old spot on the Politburo.) But those techniques are useless when elections must take in the entire state; as a result, a small group of Senate candidates must at least pretend to represent both red and blue voters.

But the real reason I love the Seventeenth Amendment is that it generates so many textual puzzles for Constitutional Law nerds like myself. Writing for The Atlantic, I have discovered that there are a lot of nerds out there, lawyers and lay people alike, and so I want to share with you a Seventeenth Amendment case decided just last week in the District of Hawaii.

First, though, a little background. The Amendment, adopted in 1913, begins with great clarity: “The Senate of the United States shall be composed of two Senators from each State, elected by the people thereof, for six years...”

But its second clause is not so clear:

When vacancies happen in the representation of any State in the Senate, the executive authority of such State shall issue writs of election to fill such vacancies: Provided, That the legislature of any State may empower the executive thereof to make temporary appointments until the people fill the vacancies by election as the legislature may direct.

Back when civics class was a thing, most of us learned that the Constitution “gives” governors the power to name Senators to vacancies caused by death or resignation. But read the above carefully. In fact, the default rule is that an empty Senate seat, like an empty House seat, is to be filled by a special election. Under the “proviso,” however, a state legislature can decide to allow the governor to make “temporary appointments” until “the people fill the vacancies by election.”

This confusing language is there because the Amendment is what scholars call a palimpsest, a document that has been partially erased and reused, allowing traces of the old writing to bleed through. The original language of the Constitution required that senators be elected by the state legislatures; one clause actually did give the state “executive” the power to “make temporary Appointments until the next Meeting of the Legislature.” The drafters of the Seventeenth Amendment included a garbled version of this option.

The text leaves a puzzle: Can the legislature “empower” the governor just to fill a vacant seat for the rest of the term?  How could that be a “temporary appointment”? What happens to the idea that the Senate is to be “elected by the people”? Where else in the Constitution do we give one person the power to appoint a constitutional official? I have done a good deal of research in the history of the Amendment, and cannot find an explanation of this provision anywhere.

I did that research while consulting with a group of Illinois lawyers who, five years ago, actually won a case under the Seventeenth Amendment. After Barack Obama resigned from the Senate, then-Illinois Governor Rod Blagojevich more or less openly conducted an auction to fill the rest of Obama’s term, ultimately naming Roland Burris. Illinois law allowed this, but we argued that an appointment for the entire term could not be “temporary,” and that the Seventeenth Amendment required a special election. Remarkably enough, the redoubtable Judge Diane Wood of the Seventh Circuit agreed with us, and the state was required to hold a special election—though the litigation took so long that it filled only the last 30 days of Obama’s term. It was a classic constitutional victory—rich in symbolism, a little hazy as to practice.

The special election issue arose again in a case called Hamamoto v. Ige, which was just dismissed by Judge Derrick Watson of the District of Hawaii. The issue is another textual riddle: When the Amendment says that a legislature can “empower” a Governor to make appointments, can it also require the governor to choose from a specified list?

Here’s what happened: In November 2010, Hawaii’s voters elected Senator Daniel K. Inouye to a ninth term. Two years later, in December 2012, Inouye died. Under Hawaii law, Governor Neil Abercrombie was required to name a temporary replacement from a list of three provided by the state Democratic Party. That replacement, Brian Schatz, ran for election to the remaining term in a special election in November 2014, and defeated Republican Campbell Cavasso by a margin of nearly three to one.

Just before that election, a Republican named John P. Roco brought a lawsuit alleging that Schatz’s appointment was unconstitutional. Roco was an odd plaintiff. He had wanted to be the Republican nominee—but he lost to Cavasso. In fact, he got only 10 percent of the primary vote. It thus seems unlikely that any sequence of events would have made him the Senator. Nonetheless, he argued that the Seventeenth Amendment allowed the legislature to “empower,” not limit, the governor. Abercrombie should have been able to name anyone he chose. Because Schatz had been selected from a group of three approved by the Democratic Party, he should be removed from office.

Roco soon dropped that demand, asking only a “declaratory judgment” that the Hawaii law was invalid. Judge Watson on February 23 dismissed the case, holding that it was past its sell-by date (or as lawyers say, “moot”). Roco and Hamamoto’s lawyers argued that the issue might arise again, but Watson rejected that argument, noting both that the plaintiffs waited nearly two years after Schatz’s appointment to bring their suit and that the legislature might change the statute before the situation arises again.

Should it? Vikram Amar, one of America’s foremost scholars of the Constitution’s text, believes that the plaintiffs are correct—a legislature can “empower” but not limit. Sanford V. Levinson of the University of Texas, equally or more eminent, disagrees.

Though they may seem arcane, these Seventeenth Amendment issues matter. Its strange wording allows legislatures to game the system. When, for example, Mitt Romney became governor of Massachusetts, the Democratic legislature took away the power of temporary appointment, requiring an immediate special election. When Edward Kennedy took ill in 2008, they quickly restored the power to Democratic Governor Deval Patrick, who in 2009 appointed Paul G. Kirk to make sure the Affordable Care Act had the votes needed to pass.

That’s the real dog I have in these obscure fights. The temporary appointment proviso inevitably leads to partisan tricks. In 2013, scholars Zachary Clopton and Steven E. Art estimated that legislatures and governors dodge the Amendment’s requirements in more than one-sixth of cases, allowing appointees to serve a total of 200 years during which the people were excluded from any say. Legislatures could, however, decide to require immediate special elections, as they do for House seats; several, including Oregon, have done so. The rest of them should do the same.

The Amendment says “elected by the people.” It’s a good rule, and we ought to follow it.

We want to hear what you think about this article. Submit a letter to the editor or write to letters@theatlantic.com.