At a time when Portland area elected officials and advocates are united in pushing for tolls along all of Interstate 5 and I-205 in the metro area, a pair of Republican legislators and others are trying a new tactic that could block the plan.

An initiative petition they've submitted to the state elections division would require a majority of Oregon voters (and a majority of voters in each county where the toll applies) is to sign off on any tolls on existing highways that aren't being expanded.

The initiative petition was first reported last week by the Portland Tribune.

Since then, State Sen. Julie Parrish (R-Tualatin/West Linn) has decided to back the measure, a decision she announced on Twitter on Tuesday.

Parrish adds new political prowess to the petition already back by State Representative Mike Nearman (R-Independence) and Gladstone Planning Commissioner Les Poole.

Parrish was a campaign consultant for Dennis Richardson's successful campaign to become the first Republican elected to statewide office in a nearly decade and a half, but failed to win the necessary votes for Measure 101, which would have blocked the taxes passed to fund the state's Obamacare Medicaid expansion.

Parrish is already campaigning for it, at least on Twitter.

The petition to require voter signoff on tolls comes in the face of unusual Portland-area unity around congestion pricing, with the Port of Portland, environmental advocates and conservative groups agreeing it could relieve the clogging on Portland's highways.