If Kyrsten Sinema left office, how would she be replaced?
It's a harder question to answer than it seems!
On December 9, just days after Democrats had seemingly secured a 51-49 majority in the U.S. Senate, Kyrsten Sinema announced that she was becoming an independent. The implications of her announcement are not totally clear—she says, for example, that “[n]othing will change” about how she votes in the Senate, and the significance of her switch for the 2024 Senate race in Arizona will seemingly play out in the coming months.
But rather than agonizing over what her announcement means for control of the Senate—after all, that’s “kind of a DC thing to worry about”—I wanted to focus on a different question altogether. What would happen if Kyrsten Sinema left the Senate prior to the end of her term?
The Seventeenth Amendment to the Constitution, which provided for the direct election of U.S. Senators, necessarily acknowledged what would happen when a vacancy occurred. It establishes a basic requirement—“the executive authority of such State shall issue writs of elections to fill such vacancies”—and allows the state legislature to “empower the executive . . . to make temporary appointments” until the special election is held.
States have adopted a variety of procedures for filling U.S. Senate vacancies. In most states, the legislature has empowered the governor to make a temporary appointment, and a special election is scheduled concurrently with the next regular election. We saw this process play out in 2020, for example, in both Arizona and Georgia. In response to the resignations of John McCain in 2018 and Johnny Isakson in 2019, the governors appointed Jon Kyl (and then Martha McSally) and Kelly Loeffler, respectively, and special elections were scheduled for 2020. A number of states require that special elections be held more immediately than that, however, and a few states even bar governors from filling the seats at all, requiring that they be left vacant until a special election.
But nine states, including Arizona, attach a condition to gubernatorial appointments to fill U.S. Senate vacancies—they must be members of the same political party as the previous incumbent. (Some commentators, perhaps most prominently Vikram Amar, have suggested that these requirements are unconstitutional, and though some efforts have been made to challenge their constitutionality, we lack a definitive ruling from a federal appellate court or the U.S. Supreme Court.)
The same-party replacement is prolific in the United States, and is used in lieu of (or in conjunction with) a special election to fill vacancies in many different offices. It’s perhaps most prominently used in the context of state legislative vacancies, starting with its adoption by Nebraska in 1911, as I’ve explored in some of my scholarship. It took a bit longer for states to adopt this procedure for U.S. Senate vacancies, but it’s slowly becoming a more popular reform as control of the Senate only narrowly shifts from one party to another.
In Arizona, the requirement is seemingly straightforward. Under section 16-222(B)(C) of Arizona Revised Statutes:
For a vacancy in the office of United States senator, the governor shall appoint a person to fill the vacancy. That appointee shall be of the same political party as the person vacating the office[.]
But even this brief requirement leaves a lot of unknowns—and very quickly, this becomes a question of statutory interpretation. What does “same political party” mean? “Same” with respect to when? Is it “same” as of when the previous incumbent was elected? As of the time of the vacancy? What on Earth do we do if the previous incumbent wasn’t a member of a political party?
Let’s start with the last question. I analyzed this question a few years ago, and the reality—perhaps surprising, perhaps not—is that very few states have adopted explicit procedures for filling the vacancies left by independent officeholders. Of course, accounting for every possible contingency caused by a vacancy is near-impossible, so perhaps this omission is understandable. Very few independents (or even members of third parties) have been elected to office in the modern era, and the odds of a vacancy aren’t terribly high, so this question hasn’t been encountered very often at all. (I was able to find just one instance, but I’m sure there are others.)
And that’s true in Arizona, too. Its same-party replacement requirement doesn’t address how independent officeholders are succeeded. It’s possible that we might be able to fall back on the Governor’s inherent power under the state constitution to fill vacancies in offices where “no mode shall be provided by the Constitution or by law for filling such vacancy,” but that’s far from clear.
So let’s turn to some of the other interpretative questions, then. “[S]ame political party”—but as of when? In the usual case, this presents no problem at all. While it’s certainly not unheard of for elected officials to switch parties, it’s not the usual case. So the typical incumbent who leaves office was elected as a member of one party, and was still a member of that party at the time of their resignation.
But elected politicians more than occasionally switch parties. Sometimes, this even happens in states with same-party replacement requirements. And in rare cases, someone is elected to office as a member of one party, switches parties while in office, and then resigns. I’ve written about how state courts have interpreted unclear statutes in these contexts, but because the interpretations are so dependent on the wording of individual statutes, there’s no “majority rule” to speak of here.
In Arizona’s case, there’s actually no need to address this complicated question because the statute contemplates the exact scenario of an incumbent who switched parties:
If the person vacating the office changed political party affiliation after taking office, the person who is appointed to fill the vacancy shall be of the same political party that the vacating officeholder was when the vacating officeholder was elected or appointed to that office.
Therefore, because Sinema was elected as the Democratic nominee in 2018, if she left office prior to January 3, 2025, she would be replaced by a Democrat of Governor-elect Katie Hobbs’s choosing.
If she was re-elected as an independent in 2024, however . . . it’s unclear! My gut says that the Governor’s inherent power to fill vacancies under the constitution wouldn’t apply here. Under the strict wording of the Seventeenth Amendment, the legislature did not “empower” the Governor to fill a vacancy in this context, and as such, my best guess is that the seat would remain open until a special election was called.