Justice Thomas Kilbride is embroiled in the most expensive Supreme Court election in Illinois history — and he doesn’t even have an opponent.

Kilbride, a Democrat who's been on the court for 20 years, is up for his once-a-decade retention, in which he must receive 60 percent of the vote to keep his job. So far, Kilbride’s Republican detractors have spent $6 million to urge a “no” vote.

Why are the Republicans gunning so hard for Kilbride? Because, thanks to the quirky way Illinois elects Supreme Court justices, it’s their only shot at controlling a branch of state government.

There are seven justices on our state Supreme Court. Three are elected, countywide, from Cook County. The rest are elected from districts that are supposed to be “substantially equal in population” to Cook County, but which haven’t been redrawn since 1963. As a result, the 2nd District, which stretches from the collar counties to Galena, has 3.1 million people, while the 5th District, in Southern Illinois, has 1.3 million. The collar counties have grown a lot since 1963. Southern Illinois has been shrinking.

Under this system, the three Cook County seats are gimmes for the Democrats, who currently hold a 4-3 majority on the court. But the Downstate districts are competitive, especially since rural Illinois has been trending Republican in recent years. Kilbride’s 2nd district, which runs from Kankakee to Moline, includes plenty of counties that voted for Donald Trump in 2016, and will again this year. If Kilbride isn't retained, the other six justices will appoint a placeholder to serve until the next election, in 2022, when the Republicans will have a chance to win a majority on the court.

The Republicans donating against Kilbride are led by financier Ken Griffin, the richest man in Illinois, who is also spending millions to defeat the Fair Tax. He’s pitched in $4.5 million. Businessman Richard Uihlein has put up $1 million.

“They’re getting the band back together from the Rauner turnaround agenda,” says Kent Redfield, professor emeritus of political science at the University of Illinois-Springfield. “They’ve got nowhere else to go. They’re not spending money on legislative elections. Why throw good money after bad?”

Kilbride’s biggest supporter is House Speaker Michael Madigan, who just gave him $550,000. In 2016, Kilbride wrote the opinion in a 4-3 ruling against allowing a “Fair Maps” constitutional amendment on the ballot. The amendment would have established an independent redistricting commission, taking the power to draw electoral maps away from Madigan, who critics say has used it to bolster Democratic majorities in the legislature and the state’s congressional delegation.

(Another Fair Maps Amendment was proposed this year, but the legislature — which is controlled by Madigan — failed to give it the three-fifths vote that would have put it on the ballot. The Better Government Association, which has long campaigned for independent redistricting, just proposed its own fair map, which would probably elect more Republicans to Congress.)

Kilbride is also a swing vote on issues such as tort reform, workers’ compensation and collective bargaining, which are important to the trial lawyers and labor unions that have donated a total of $3.8 million to his campaign.

To Redfield, so much money, paying for so many negative ads and mailers flooding north-central Illinois, is a sign that Illinois needs to stop electing Supreme Court justices.

“This is what happens when you elect judges in the current atmosphere and the current rules for spending money,” he says. “When judicial elections look like every other nasty, partisan, hyper-expensive election, citizens come to think of judges as partisan politicians, which is corrosive to the legitimacy of the Courts and the judicial process.”

Redfield would like to see Illinois’s Supreme Court elections replaced by the “Missouri Plan,” in which a non-partisan panel submits a list of qualified candidates to the governor, who then selects a new judge. Currently, more than 20 states use some form of this system. The Brennan Center for Justice came to the same conclusion in its 2018 study “Choosing State Judges: A Plan for Reform.”

Twenty-two states provide for contested supreme court elections, where multiple candidates can vie for a seat on the bench. These competitions should be replaced by a publicly accountable appointment system that is transparent and minimizes opportunities for political self-dealing. Likewise, the 19 states that use retention elections, where sitting justices must stand for uncontested up-or-down votes to retain their seats, should eliminate them.

We therefore urge states to adopt a “merit selection” appointment process, in which an independent nominating commission vets judicial candidates and issues a short list. The governor then selects an appointee from the list provided to her.

Of course, changing our system of choosing Supreme Court justices would require a constitutional amendment, which would have to get through the state legislature, which is controlled by Democrats who like the system the way it is. For now, we'll have to keep ponying up for (or against) our favorite (or least favorite) justices.