Hennepin County Commissioner Mike Opat said he was doing it for the Bottineau light-rail line from Minneapolis to Brooklyn Park. Washington County Commissioner Lisa Weik said she was doing it for the bus rapid transit Gateway line from St. Paul to Woodbury.

These members of the Counties Transit Improvement Board (CTIB) voted Wednesday to rescue the Southwest light-rail line from the jaws of defeat not because they are enamored of improving transit between Eden Prairie and downtown Minneapolis.

Rather, Opat and Weik explained before voting to add $20.5 million to the CTIB’s Southwest support, they understand this reality: For the Twin Cities to have a chance at the federal funding that the remainder of a planned rapid transit system will require, it must proceed now to build the long-planned 14.5-mile extension of the Green Line to the southwest.

Drop those plans now — after $140 million in public funds already have been spent to complete 90 percent of required engineering and design work, and after procurement of the train’s cars is already in progress — and this region will damage its good standing with the Federal Transit Administration. Not only would Southwest’s expected $929 million in federal funds go to some other city, but the Twin Cities’ ability to obtain the federal funds needed to build Bottineau, Gateway and other rapid transit lines on metro planners’ drawing boards would be compromised.

That sound assessment carried the day for the Southwest line this week. Three local and regional entities — the CTIB and the Metropolitan Council on Wednesday, and the Hennepin County Regional Railroad Authority on Tuesday — answered Gov. Mark Dayton’s call to provide the final $144.5 million in Minnesota matching funds needed for Southwest to meet federal requirements.

Each body acted within its existing legal authority. But the CTIB and the Metropolitan Council made a fiscally and politically uncomfortable stretch to plug a funding hole created by the refusal of the Republican-controlled Minnesota House to make any accommodation that would allow Southwest light rail to proceed.

As a result, while the Southwest line has been salvaged, uncertainty still hangs over the rest of the rapid transit lines planned for the region. Stopping Southwest now would have put future lines in jeopardy. But propelling Southwest forward with the limited funding tools the Legislature allotted to county and regional governments — and over the vociferous objection of Republican elected officials — is almost as risky. It leaves insufficient means to pay for the next lines on the build-out schedule, as well as a residue of partisan ill will.

That’s why, despite this week’s apparent resolution of the Southwest funding dilemma, the future of transit in the metro area and transportation throughout the state are still at stake in this fall’s legislative campaigns.

Underfunding threatens to stymie not only Metro Transit’s rapid transit expansion plans, but also Greater Minnesota transit and highway improvement projects throughout the state. Without a Legislature that’s willing to push past political gridlock and provide additional funds for transportation over the long term, next year will bring far fewer road construction projects — and, despite the good intentions of county commissioners Opat and Weik, Southwest still could be the last rapid transit line built in the Twin Cities.