Legislation giving Michigan ballot drives a firm window of 180 days to collect voter signatures has been sent to Gov. Rick Snyder for his signature.
The Republican-led Senate enrolled the bill on Tuesday.
It was proposed in response to efforts by marijuana legalization and anti-fracking advocates to persuade the state elections board to make it easier to use older signatures typically deemed void.
Republicans say a 180-day limit has effectively been in practice for decades, even with the law letting groups rebut a presumption that signatures collected outside 180 days are stale or void by proving voters were registered at the time.
Democrats say the legislation would diminish citizens' power to seek change at the ballot.
Snyder, a Republican, has not said if he will sign the bill or not.
