When they rejected a state-run health insurance exchange — an idea supported by many business leaders — Idaho legislators governed by ideology.

That was this year. Will 2013 be any different, when lawmakers wrestle with another health care issue, expanding Idaho’s Medicaid program?

I hope so. And I actually think this could be more than just unfounded optimism.

The obvious difference is the timing. The 2012 health exchange debate, such as it was, coincided with the Legislature’s waiting game on the U.S. Supreme Court’s ruling on the federal health care law. Some lawmakers assumed the court would declare the law unconstitutional, and they saw no need to create an exchange — an online health insurance marketplace, and one of the law’s hallmarks.

Their assumptions on constitutional law shot, legislators must decide again where they stand on an exchange. (The clock is ticking. States have until November to make plans to create an in-house exchange, or accept one of the feds’ making).

Meanwhile, lawmakers have another big question, courtesy of the Supreme Court: whether to accept federal dollars to expand Idaho’s Medicaid program. According to 2010 U.S. Census Bureau data, 83,000 to 138,000 uninsured Idahoans could qualify for the coverage — and at the outset, the feds would cover the entire bill. By 2020, states would have to cover 10 percent of the bill, if they choose to expand the program.

That’s where the issue gets dicey for legislators, who have watched the state’s share of Medicaid costs mushroom, largely at the expense of public schools and higher education. I can understand the hesitancy — but this is, ultimately, a math problem. Elected officials can solve puzzles of this kind, if they focus on the math and check their ideology.

This week, Betsy Russell of the Spokane Spokesman-Review crunched the numbers and arrived at an eye-opening conclusion. Expanding Medicaid would greatly ease the pressure on the state’s catastrophic health care fund. The so-called “CAT fund” ran $51 million in 2011-12 and is expected to top $60 million this year, with money coming from state coffers and local property taxes. By accepting the feds’ help on Medicaid, Russell said, Idaho could save $380 million over six years.

That’s a compelling number — certainly enough so to frame the debate. Any legislator or candidate who flatly rejects Medicaid expansion is speaking from ideology. It’s really that simple.

Gov. Butch Otter established the right tone by appointing a task force to study this decision. Otter’s work is by no means done, though. Don’t forget that he voiced support for a health exchange before the 2012 session. But he undercut his own case by claiming, erroneously, that refusing to create an exchange would jeopardize $300 million in federal Medicaid funding. Discredited on the math, Otter stood by as the debate turned on ideology.

Can the governor and legislators do better by their constituents on the Medicaid issue? I hope so.

A LITTLE MORE DYNAMIS ...

Sometimes, one editorial just won’t cut it. Not when a government project turns into a Dumpster fire on the order of the proposed Dynamis plant.

So, for those trying to keep up, here’s a little more random ridiculousness that didn’t quite fit into our Wednesday editorial:

Æ Were it not for Commissioner David Case, it’s unlikely the county would have ever made public a letter from its engineer, requesting that the county launch a professional peer review of the Dynamis technology. The county rejected a Statesman public records request, claiming that Jim Farrens’ letter constituted a personnel matter.

State law does carve out an exemption for personnel records — but by no means is it a blanket exemption. On Tuesday, Case took matters into his own hands, releasing the letter. Well played, commissioner.

Æ On Tuesday, Commissioner Rick Yzaguirre shut down Ken Lamkin, a Dynamis opponent who wanted to address the board. In so doing, Yzaguirre kept intact the county’s unblemished but inexcusable record: no public hearings on a project that has received $2 million from the county for design work.

Of course, the county did hold a public hearing — regarding print work for election documents. So, if you’re losing sleep over the release of dioxins from a stack of copies, well, you had a chance to have your say.

Æ And for that, presumably, we can thank lame-duck Commissioner Sharon Ullman. Have I reminded you recently that Ullman, in her pre-commissioner life, was awarded the Idaho Newspaper Foundation’s inaugural Max Dalton Award for championing open government?

You can’t make this stuff up.

Kevin Richert: 377-6437, Twitter: @KevinRichert