With 99 percent of the votes counted, Missouri voters appeared set to reverse changes they made to the redistricting process two years ago aimed at making the statehouse more competitive.

Unofficial results as of midnight Tuesday showed Amendment 3 poised to pass 51 percent-49 percent despite a well-financed campaign to defeat it.

Assuming nothing changes, the result would be a huge victory for the Republican lawmakers who sponsored it in an effort that could very well save their supermajorities.

A little explanation: Prior to 2018, districts were to be drawn by bipartisan commissions appointed by the governor, with a focus on drawing compact shapes.

But under those rules, some felt the maps were unfairly tilted toward Republicans.

In 2018, Republicans won an average of 57 percent of the two-party vote across 163 state House districts, but took 71 percent of the seats.

Clean Missouri created a new demographer position to draft districts aimed at producing more competitive elections and an assembly that better reflects the statewide vote, where the two parties are often more evenly matched than they are in the Republican-dominated statehouse.

The half-Republican, half-Democrat commissions still review the maps, but they can’t override the demographer unless 70 percent of committee members agree.

An Associated Press analysis suggested the new formula could bolster Democrats’ chances in 2022, after the current census, and ultimately end Republican supermajorities, which can pass legislation over a governor’s veto without a single Democratic vote.

Amendment 3 would scrap the demographer and put concerns about competitive elections on the backburner.

The old bipartisan commissions would again control the process and appellate judges would back them up if they deadlock.

Republicans said their amendment was needed to avoid having maps with “spaghetti” string districts combining urban, suburban and rural areas drawn to make races more competitive, though opponents disputed that.

It would also make another key change: allowing mapmakers to calculate the population of each district without counting immigrants, children and nonvoters.

Researchers who supported Clean Missouri said such a change would strengthen the influence of old, white and rural Missourians — who largely vote Republican — at the expense of minority communities and young people.

Amendment 3 would also limit lobbyist gifts to lawmakers by banning all gifts from paid lobbyists. It would not ban gifts from unpaid lobbyists and lobbyists related to a legislator within the fourth degree, including first cousins, however.

It would also reduce the amount an individual could donate to a Missouri Senate candidate's personal campaign committee by $100, from $2,500 to $2,400.