The motivation spurring backers of Idaho’s Proposition 1 is noble.

They want to increase funding for public schools from kindergarten to 12th grade, including charter and virtual schools, by about $219 million.

They make good arguments for their ballot measure, too: Idaho ranks 45th in the nation on what it spends on public education. It has the nation’s eighth most crowded classrooms. It ranks 44th in percentage of high school graduates going on to college. Additionally, they can point to the annual public policy survey by Boise State University in which Idahoans consistently single out public education as the top issue for more state funding.

The Invest in Our Kids’ Education Campaign has identified a problem and appears to have gale-wind support for their proposition.

But Proposition 1 has a fatal flaw. It is an attempt to mandate state spending at the ballot box, which is always a dicey proposition. To come up with the enormous amount of revenue required by this measure, the Legislature would have to raise the sales tax again. Or hike other taxes, such as the beer and wine tax, the income tax or even property taxes. Or cut spending dramatically. Or eliminate sales tax exemptions. Or approve a combination of these options. No one would argue against spending cuts. A review of sales tax exemptions would be good, too. However, a take-it-or-leave-it measure handcuffs lawmakers and removes the opportunity for a deliberative approach.

Idahoans should vote against Proposition 1.

Originally, Proposition 1 identified a revenue source that was palatable: a penny increase in the 5-cent state sales tax. A penny is a marginal amount to pay for higher teacher salaries, smaller classrooms, textbooks and supplies, and other areas targeted by proposition backers. But that penny was snatched by Gov. Jim Risch and legislators in August to remove school maintenance and operations costs from the property tax. Already, experts are predicting that the tax shift will have a dramatic effect in holding down property taxes in growing North Idaho areas.

As a result, however, the Idaho sales tax increased to 6 cents on Oct. 1, triggering a clause in Proposition 1 that requires the lawmakers to appropriate an amount of money equivalent to a penny in sales tax to fund the measure’s mandates – about $219 million. It’s doubtful that Idahoans want to see another sales tax hike. Also, it’s debatable whether lawmakers can find more than $200 million in new taxes or spending cuts when they’re constantly facing the revenue demands of budgets such as health and welfare, corrections, and higher education. Proposition 1 elevates teacher salary demands over those of other state workers.

Unquestionably, legislators can do a better job in funding education, although they deserve credit for regular increases in spending for public schools, which now consumes $1.03 billion of the state’s $2 billion budget. Legislators also have done a mediocre job in performing their court-recognized constitutional duty to provide safe school buildings for Idaho’s children.

But budgeting by ballot is a poor way to address funding problems.