In Washington state’s Parliament this year, the minority party ruled on the most important matters.

Frequently in the regular and special sessions, conservatives hunkered down on one side of a potent issue and liberals dug in on the other.

Neither alliance could succeed unless it coalesced with those in the Roadkill Caucus, a collection of moderates more accustomed to getting run over than courted by the political left and right.

Bipartisanship is what the governor and legislative leaders called it. Governing by coalition, like one might see in a parliamentary system, is a more apt description.

Moderates, all business-friendly Democrats, arrived in January determined to make their influence felt by behaving as their own bloc.

They succeeded in the Senate. Democrats outnumbered Republicans but when this group united with the minority Republican caucus it created a philosophical majority which ruled with a strong, and at times intractable, hand to the final day.

The moderates shifted the balance of power by switching sides. They forced their caucus’s leaders to do things they didn’t intend to do, like letting Republicans write chunks of the budget.

Similarly, they forced changes in the 100-year-old workers compensation system. In the Senate, moderate Democrats locked arms with Republicans in wanting lump sum buyouts added as an option. Together they resolved not to concede to the liberal Democrats running the House — a stance which arguably forced the special session.

Over time, and through hours of negotiation, they eventually secured a compromise which gets their foot in the door for bringing voluntary settlements into the system.

But down the stretch, this philosophical majority governing the Senate had its limits tested when on one issue Republicans dug in a bit deeper than their moderate teammates wanted.

It happened in a fight over whether to put a constitutional amendment on the ballot dealing with the state’s debt. Republicans insisted on its passage before they’d condone any action on the operating budget.

Most House Democrats opposed the ballot measure. These liberals felt the Senate coalition had won enough political points this session and weren’t going to get this one, too.

A stand-off ensued, threatening to push lawmakers into a second special session, until a few of those roadkill members made known they weren’t in lockstep with their GOP mates. That helped push along a compromise.

Where do these moderates go from here? Will they draft an agenda of their own or be content to team up with one side or the other, depending on the issue?

Next year’s big battle is going to be transportation. A revenue-raising measure will be prepared for the ballot. It will be a difficult fight and probably pretty partisan.

Members of the Roadkill Caucus will almost certainly be casting the decisive votes on which taxes or fees are in the package.

Knowing this, liberals and conservatives should start building bridges with them. There are only seven months to go before Washington’s Parliament, er Legislature, reconvenes.

Political reporter Jerry Cornfield’s blog, The Petri Dish, is at www.heraldnet.com. Contact him at 360-352-8623 or jcornfield@heraldnet.com.