AMONG THE WAYS that Massachusetts is unique among the 50 states: our state election ballots give top billing to incumbent state officeholders who are seeking re-election, with the other candidates listed in alphabetical order below. (Cities and towns can choose alternatives – Boston, notably, selects candidate order by lottery.)

No other state reserves the top ballot positions for incumbent candidates. Most states determine ballot order either by lottery or by rotating names among precincts, so as to avoid the “primacy effect” – the name psychologists give to the human inclination to select the first item on a list over those further down. Some states do recognize current officeholders on their ballots, not by listing the name first, but by some indication of the incumbent’s status next to it. Here in Massachusetts we do both – we put the incumbent’s name at the top and garnish it with the words “candidate for re-election.”

Studies of the primacy effect in voting have concluded that it has some influence. Its weight is more significant in primary elections than in general elections (where party affiliation also differentiates the candidates), and it’s most likely to play a role in low-profile elections, down-ballot races, and contests with many candidates. Bottom line, it can matter.

And it can matter enough to amount to a violation of the constitutional right to equal protection of the laws. In 1975, the California Supreme Court ruled in favor of a non-incumbent city council candidate challenging that state’s incumbent-first statute. Concluding that the law imposed “a very real and appreciable impact on the equality, fairness, and integrity of the electoral process,” the court struck it down as an infringement of the equal protection rights of voters who chose a candidate lower down on the list. In compliance with that decision, California has since adopted a ballot rotation system.

The incumbent-first law in Massachusetts still stands, however. A legal challenge here, decided one year later, had an entirely different result.

The 1972 Democratic primary election for two Middlesex County commissioner seats pitted two non-incumbent candidates (one of whom was Lowell city councilor Paul Tsongas) against two incumbents.  Weeks before the election, the challengers filed a lawsuit seeking to invalidate the incumbent-first law on equal protection grounds. The court declined to intervene before the election, and Tsongas and his fellow challenger ended up winning the two spots, which made their legal claims moot. New plaintiffs joined the case, and after a trial a three-judge panel of the federal district court issued a decision upholding the law.

Unlike the court in California, which found that the incumbent-first law had “a very real and appreciable impact” on elections, the Massachusetts court viewed the evidence as far more equivocal, and it questioned how strong any advantage accruing to incumbents could be, given the many other factors (some rational, some less so) influencing voters’ decisions. The court may also have had in mind that the original plaintiffs won their contests, which tended to disprove the influence of the incumbent-first law, but its opinion did not include that example as a reason for skepticism.

Any evidence of bias attributable to the incumbent-first rule, the court concluded, was insufficient to overcome the state’s legitimate interest in educating the electorate with information about what the court declared to be the most important decision voters must make — whether to retain or to replace the incumbent. The case was dismissed, with the court’s verdict in favor of the Commonwealth summarized in this memorable sentence: “Voters have no constitutional right to a wholly rational election.”

The plaintiffs did not appeal and so the incumbent-first statute remains the law in Massachusetts. To be sure, as the court noted, the Legislature is free to adopt a different statutory scheme, but in the 45 years since the district court decision, it has not.

Until recently, the only legislative support at all for changing the status quo came from  members of the Republican party – and only a few of them. Sen. Bruce Tarr of Gloucester, the GOP’s Senate leader, filed the necessary legislation several times, but only a couple Republicans joined him as co-sponsors, and he has since stopped filing it.

Last year, unsuccessful Republican Secretary of State candidate Anthony Amore took up the cause on behalf of his party, arguing in CommonWealth that “legislative roadblocks implemented to maintain one-party rule” like the incumbent-first law are endangering our civic well-being and removing them would help restore the state to bipartisan health.

Among the ironies of this argument is that the law that the author finds damaging to democratic governance in general and his party in particular was enacted by Republican majorities. Hard as it is to imagine during this long period of Democratic control, the Republican Party once dominated the Legislature — and for an even a longer time.

Republicans enjoyed majorities in the Massachusetts Legislature for nearly a century, starting in 1856, when they routed the Know-Nothings. They held control during a two-decade period when, on three different occasions, the Legislature indulged the electoral vanity of its incumbents: first, in 1926, passing the law requiring that the words “candidate for re-election” accompany the incumbent’s name on ballots, next, requiring that incumbent candidates be listed first in primary elections, and finally in 1948, requiring that incumbents be listed first in general elections.

(And because ironies travel in packs, and nothing in politics is fool-proof, the election of 1948 was not only the first general election requiring incumbents’ names to appear at the top of ballots, it was also the beginning of the end of the GOP’s legislative reign. That year Democrats gained a slim majority in the House for the first time in nine decades, managed a 20-20 tie in the Senate, and took five state constitutional offices away from Republican incumbents.)

During the past two legislative sessions, the bill to nullify the ballot advantages for incumbents has been filed by a Democratic legislator, Rep. Mindy Domb of Amherst.

The town of Amherst’s recently amended charter provides that the order of candidate names in its municipal elections be determined by lottery. Domb’s bill would do the same for state elections and also would end the practice of identifying incumbents with the words “candidate for re-election.”

The Election Laws committee has held its hearing on Domb’s bill for the 2021-2022 session, and its decision is due in February. If the pattern of the past eight legislative sessions holds true again, the bill will be disposed of by the usual means, the study order. It has yet to receive a favorable committee report.

Heather Gerken, an elections law expert and now dean of Yale Law School, told the Boston Globe in 2004 that it’s surprising the law is still on the books in Massachusetts given the movement nationally away from protection for incumbents. “Incumbents already have so many advantages going into an election that anything you can do to reduce that advantage is likely to be a good idea and make for more competition,” she said.

In Massachusetts, however, repealing a law that favors incumbents requires a body consisting only of incumbents – the Legislature – to take action.

Margaret Monsell, a former assistant attorney general and former general counsel to the state Senate Committee on Ways and Means, is an attorney practicing in the Boston area.