The measure was changed Saturday by Senate Finance Committee members to require petitioners seeking a spot on the ballot to get a minimum number of signatures in each of Nevada's congressional districts.

That standard has passed constitutional muster in recent court rulings because such districts tend to have roughly equal numbers of voters.

But Care, echoing comments Saturday by Lee Rowland of the American Civil Liberties Union of Nevada, said questions remain because provisions of the bill would expire in mid-2011 and an "undefined notion of a petition district" would remain.

State Sen. Bob Coffin, D-Las Vegas, backed SB212, saying wealthy individuals trying to "drive their own agenda" have used petitions to undermine the legislative process.

The original wording of SB212 called for petition-circulators to get signatures amounting to at least 10 percent of the voters who cast ballots in each of Nevada's 42 Assembly districts in the preceding election, a plan that was challenged on constitutional grounds.

Lawmakers discussed using Nevada's higher education system regent districts for the ballot question rules, but the ACLU noted widely varying numbers of voters in both the Assembly and regent districts and said such disparities would prompt court challenges.

The latest efforts by lawmakers follow a U.S. District Court judge's ruling last year that rejected Nevada's initiative petition requirements seeking to compensate for different population sizes in urban and rural counties.

The ruling struck down rules approved by the 2007 Legislature that forced petition-gatherers to get signatures from 10 percent of the voters in each county rather than 10 percent statewide.