To recoin a phrase, a penny here, a penny there, and another half penny, and pretty soon you’re talking about a lot of money.

Several groups want to increase the Idaho sales tax at least a half penny to support their causes.

Short-term Idaho Gov. Jim Risch would sign off on a half-cent increase to the current 5 percent tax, if the Idaho Legislature passed legislation to use it for property tax relief in a possible special session this summer. Others will make their case for raising the sales tax one penny when an initiative to increase state education spending lands on the Idaho ballot this fall. Meanwhile, Kootenai County commissioners are mulling another campaign to push a half-cent, local-option sales tax to fund a possible $55 million expansion of the county jail.

That’s a minimum of two additional pennies of sales tax and a possible maximum of 2.5 cents, in the off chance that the Legislature not only meets this summer but approves legislation supported by the Idaho House this spring to add a full penny for property tax relief. That may be too much. Ask Washington residents who pay more than 8 cents in sales tax. Idahoans should let Gov. Risch and other elected representatives know now what they think of these proposals.

As matters stand, Gov. Risch took another step toward calling a special session Friday when he alerted lawmakers to be ready to meet Aug. 25.

Risch has correctly assessed that property tax relief is the most important proposal among the three.

In North Idaho, a hotbed of anti-tax sentiment that has embraced the tax-limiting One Percent Initiative in the past, property taxpayers were staggered a few weeks ago when they received notice that their assessments increased an average of 40 percent in a single year. Without tax relief, they will rebel again. Without relief, they will stop supporting school bonds and levies as Coeur d’Alene did this spring when voters rejected a key capital facilities levy.

The governor, who would grant property tax relief by shifting school maintenance and operation costs to the sales tax, should follow through with his special session and let proponents of the other two worthy proposals fend for themselves. Many North Idahoans would willingly trade property tax relief of about 20 percent for an additional penny of sales tax, which would be paid by visitors and tourists, too. In Kootenai County, voters may also be willing to approve a half-cent, local-option tax to expand the jail beyond its 325-bed capacity, if organizers couch their argument for the increase in terms of property tax relief. Idaho law requires local-option taxes to be split between jail construction and tax relief.

School funding, of course, is more important than building jails.

Proponents of Proposition One, which would provide about $200 million in new education revenue by raising the state sales tax by one penny, have bipartisan support across the state and from the two major gubernatorial candidates this year. Traditionally, Idaho ranks low compared to other states in per-student spending and high school graduates going to college, and high in classroom crowding. As a result, Idahoans routinely tell pollsters they support increased education funding.

If the sales tax is raised by legislative fiat this summer, it’ll be interesting to see whether they feel the same about Proposition One this fall.