When Missouri voters were asked last year whether they wanted to increase the minimum wage and require employers to provide paid sick leave, 58 percent of them said yes.

Not long after that vote, the Republicans who control the state government mobilized to unwind those changes. On Thursday, Gov. Mike Kehoe, a Republican, signed into law a bill that limited the voter-approved minimum wage increase and scrapped the paid sick leave requirement altogether.

The new law in Missouri reflects the growing impatience of Republican leaders with left-leaning groups that use state ballot questions to circumvent conservative legislatures and bring policy proposals directly to voters. In Missouri, recent ballot questions have restored abortion rights, expanded Medicaid and legalized marijuana, all causes that Democrats generally support, even as Republicans have won statewide elections in landslides.

Liberal groups have used a similar playbook in other Republican-led states that allow ballot questions, leading lawmakers in some places to try to make it harder to place questions on the ballot or to try to increase the threshold needed for a ballot measure to pass. But the move by Missouri Republicans to undo much of a voter-approved measure just months after it passed represented an escalation in the struggle over ballot measures.

“Passing this bill makes a mockery of the democratic process itself,” State Representative Mark Boyko, a Democrat from suburban St. Louis, said during a debate earlier this year.

The changes that voters approved last year established mandatory paid sick leave for Missouri workers and called for raising the state’s minimum hourly wage to $15 in 2026, with increases in subsequent years to be determined by the Consumer Price Index.