Utah Attorney General Mark Shurtleff says Utah's law allowing only people in a proposed new school district to vote on a district split is likely to be upheld in court — contrary to the viewpoints of a Jordan School District attorney and some west-side Salt Lake County mayors, who look to sue over the issue.

The opinion by the Attorney General's Office, officially requested by House Speaker Greg Curtis, R-Sandy, was made public Wednesday.

"The new law clearly raises constitutional concerns, and if a city votes to split off from an existing school district, there will likely be a legal challenge," the opinion states. "As you know, how the courts will rule depends to large extent on the standard of review they follow, and whether they will apply federal or state law. As set forth in the following legal analysis, it is the opinion of the Office of the Utah Attorney General that there is a substantial likelihood that the courts will uphold SB30."

But Riverton Mayor Bill Applegarth is not so sure.

"I think there's enough doubt here that it needs to go to court," Applegarth said.

Alta, Cottonwood Heights, Draper, Midvale and Sandy all have voted to let their residents decide whether to break away from the Jordan School District. In a separate movement in Granite district, elected leaders are poised to vote on putting the question to Holladay, South Salt Lake and Millcreek township voters in the coming weeks.

Several west-side officials contend that SB30, passed during the 2007 legislative session, is unconstitutional under the 14th Amendment's guarantee of one man, one vote. As the law is written, only voters in cities proposing to split from a school district would vote on the issue.

But Shurtleff says the legal issue comes down to cities' responsibilities to their residents.

"The right to vote is a pretty substantial right," he said. "If there's a voting question, the courts will often apply a higher standard. But there are voter qualification cases where courts have said no. This is different because we're not dealing with the right to vote."

The state law in question recognizes the duties of local governments to look after their residents, so they can make a decision for themselves to withdraw from a school district and not have another city intervene, Shurtleff said.

The 11-page opinion ponders the ins and outs of both state and federal case law, and laws of other states.