You can tell all you need to know about the irrelevance of the Hawaii GOP as an opposition party by the cheerleading of two of its most prominent elected officials for the deficit-ridden Oahu rail project.

Rep. Bob McDermott, one of five Republican state legislators and a candidate for governor next year, ripped Gov. David Ige for not immediately calling a special legislative session to ram through another rail excise tax extension for a project that’s nearly $5 billion over budget and growing.

He dismissed concerns of House Democrats about indefinitely extending a tax that was promised to last only 15 years by saying, “We’re already paying it, and the sky isn’t falling.”

Now there’s a rock-ribbed Republican tax philosophy.

City Councilwoman Kymberly Pine, the only Republican on the Council and a future mayoral aspirant, promised a year ago to present a plan to finish rail all the way to Ala Moana without further tax increases.

But there she was during the Legislature, prominent at Mayor Kirk Caldwell’s side, pressing for some $3 billion in new taxing authority for rail while soft-pedaling the gross mismanagement and broken promises.

Pine argues voters never would have approved rail if they knew it might stop at Middle Street or Aloha Tower. Fair enough, but it’s also fair to say voters never would have approved rail if they knew it would end up costing $10 billion to $15 billion.

It’s no surprise, or a problem, that McDermott and Pine support rail; they both represent West Oahu districts that benefit most from the train.

The problem is their lack of leadership you’d expect from an opposition party in demanding the city correct its clueless rail management and out-of-control spending.

McDermott’s essay in Honolulu Civil Beat pitching more taxes to finish rail didn’t have a single word calling for better cost efficiency.

Leeward lawmakers who have the most at stake should have protected rail by voicing the loudest demands for responsible cost management.

Instead, they kept mostly silent as missteps multiplied, enabling the city to avert needed course corrections. If rail fails, it’s on them.

The only current elected Republican to come down hard on rail accountability is Rep. Cynthia Thielen, who says extending the excise tax would “convert a disappointment into a disaster” and reward “reckless hubris and aggressive incompetence.”

Rail sycophants in the GOP caucus dismiss her as a Windward legislator who can politically afford to critique rail.

Most Windward folks are happy to help pay for a workable traffic solution for gridlocked Leeward neighbors.

They don’t support paying for more deceit, ineptitude and waste — and the same is increasingly true of Leeward residents.

They’re alarmed that the likes of McDermott and Pine are so OK with this grand larceny model of public works.

Reach David Shapiro at volcanicash@gmail.com.