RIVERTON — It's the junior prom all over again for Riverton Mayor Bill Applegarth.

As a high school junior, a teenage Applegarth and his group of friends decided they would all go to the prom. Realizing he didn't have a suit and that he couldn't wait until the last minute to find one that fit his then-lanky 6-foot-4, 165-pound frame, he bought one early.

"Then all my friends backed out on me," Applegarth said. "I didn't wear that suit until my senior prom."

The Riverton mayor shared that story during Tuesday night's City Council meeting to describe his feelings about the faltering coalition of west-side cities that had been poised to challenge the constitutionality of a law that allows cities to break away from existing school districts and form smaller ones.

Applegarth contends that the new state law is unconstitutional because a city or group of cities can split from a school district without a vote of the entire district. And that, the mayor said, violates the 14th Amendment's guarantee of one man, one vote.

Feasibility studies for proposed splits indicate that Riverton and its fast-growing southwest Salt Lake County neighbors Herriman and Bluffdale would struggle financially to keep up with all of the new schools that will be needed over the next 10 to 15 years.

Significant property-tax increases would be needed for construction costs alone. Operating and maintaining the schools and attempting to provide the same quality of education and class options as the existing Jordan School District likely would require additional tax hikes, city leaders said.

Riverton is hoping to stop that domino effect with a legal challenge of the law, but elected leaders aren't sure the city can shoulder the financial burden of a lawsuit alone. Originally, a coalition of six west-side cities — Riverton, South Jordan, West Jordan, Herriman, Taylorsville and Bluffdale — had expressed interest in splitting costs of the legal challenge.

West Jordan drifted away from that group in recent months as it began exploring the idea of forming its own school district. The West Jordan City Council voted Tuesday night to put the split on the ballot in November.

Action by the state Legislature during a special session last week — taking the Salt Lake County Council's say on a Jordan split out of the equation and lowering the the minimum population required for a new school district from 65,000 to 50,000 — further fractured the west-side alliance.

"The Legislature kind of split our ranks," said Taylorsville Mayor Russ Wall.