The decision of state Sen. Andy Hill to not take on Gov. Jay Inslee in 2016 forced the Democratic Party attack machine to brake hard and return to the shop.

Its operators had invested much time into manufacturing salvos to launch at the Redmond Republican who they presumed would be the Democratic governor’s opponent next fall. In recent months, these Democratic operatives even test-fired a few in Hill’s direction.

Now they need to restock and reload for what appears to be a battle with a man they’ve mostly ignored — Bill Bryant, a mild-mannered and widely unknown member of the GOP mainstream who is an elected Seattle port commissioner.

As elated as the Democratic muscle is with not having to tackle Hill, it’s hard not to imagine they (and maybe Inslee, too) are suffering a bit of a letdown as well.

They expected the governor would face as tough an election in 2016 as he did in 2012. Yet one by one, those with the seeming potential to mount such a challenge have chosen not to do so.

Rob McKenna, who lost to Inslee in 2012, signaled he wasn’t seeking a rematch. State Sens. Bruce Dammeier of Puyallup and Steve Litzow of Mercer Island also have said no.

Congressman Dave Reichert is still talking himself up for the race but seems unlikely to talk himself into it.

If Bryant winds up the Democratic Party’s chief target it means he’s also the Republican Party’s torchbearer.

That’s going to take some getting used to for GOP leaders. Unseating Inslee is a top priority but they, much like Democrats, had kind of counted on having a better known personality taking on the governor.

Republican leaders must decide how much the state party will invest in a Bryant bid. There’s a risk that anything perceived to be less than all-in will be deemed a concession they don’t believe Bryant can win.

In 2012, the party contributed $2 million directly to the McKenna campaign and another $500,000 of in-kind contributions, according to campaign finance reports filed with the Public Disclosure Commission.

Nearly all of that arrived in the general election so there’s plenty of time to watch how Bryant’s campaign evolves and political events unfold.

Meanwhile, those guiding the Republican Governors Association are hashing through the same kinds of questions.

In 2012, the RGA made its presence felt in Washington when it shelled out roughly $9 million in ads and mailers against Inslee. RGA officials have yet to signal a willingness to expend that much again.

They, too, want to see if Bryant’s campaign can raise money and build an organization capable of taking on — and taking down — an incumbent governor in a state that hasn’t elected a Republican governor in 35 years.

Bryant on Monday picked up the endorsement of Dan Evans, a former three-term Republican governor. Backing from another venerable Republican is due to be announced next week.

Bryant’s aides say the campaign is exactly where it is supposed to be at this stage.

Still this is not how leaders of the Grand Old Party envisioned the campaign would be playing out.

Neither did the Democrats.

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