"This direct prohibition of the subject of an initiative brought otherwise within the conditions, manner and time restrictions imposed by law is beyond the power of the Legislature to enact," wrote Justice Michael Wilkins in voiding SB53.
The unanimous opinion noted that the Utah Constitution gives both the Legislature and the people equivalent power to enact or change legislation.
SB53, sponsored by Sen. Brent Goodfellow, D-West Valley City, sailed through this year's general legislative session and was signed by the governor in March. It took effect in early May.
As worded, it barred voters from launching initiatives regarding land-use ordinances. It also prohibited them from putting the implementation of a land-use ordinance to a public vote.
The appellate case of Sevier Power Co. v. Hansen was the first to test the fledgling statute.
Sharlene Hansen and other Sevier County residents joined a grass-roots effort seeking a ballot measure to see if voters approved of plans to build a coal-fired power plant in Sigurd.
They gathered enough signatures to get a place on November ballot. But 6th District Judge Wallace Lee, citing SB53, removed it.
Last week, Utah's high court ordered the measure back on the ballot - and, on Friday, issued the decision tossing out SB53.
"When we started out in February 2008, we believed we were doing a countywide right to vote," said Elaine Bonavita, a Richfield resident who helped spearhead the initiative effort. "But because of SB53, we now can say we played a part in restoring the right to vote to all Utahns."
In an April letter to Sevier County Attorney Dale Eyre, Assistant Attorney General Thom Roberts advised that courts could overturn SB53 because it infringed on a basic constitutional right.