The build-out of a rapid transit network is too important to the Twin Cities' future prosperity to be put at risk by one political party's shortsighted opposition. That's the thinking behind Gov. Mark Dayton's decision to seek a patchwork of local financing to salvage the ready-to-build Southwest light rail line, which has stalled because of Republican opposition in the Legislature.

Dayton's decision is the right one in the face of a bad situation. The alternative would be to kill the 14.5-mile Southwest project. That would turn down a proffered $928 million in federal funds, which would flow instead to other cities; bring no return on $140 million already expended on the project (including $30 million in state funds); cast aside seven years of planning and citizen input that resulted in unanimous consent by local governments along the line, and jeopardize the chance to win federal funds for other Twin Cities transit lines in coming years.

It would also miss a rich opportunity. Some 175,000 jobs are now situated near the proposed line from downtown Minneapolis to Eden Prairie. Build it, and that number is projected to swell to 250,000 in the next two decades. Unlike buses, rail transit is a proven catalyst for economic development.

Southwest has been described as "a train to equity." It stands to link Minnesota's largest concentration of underemployed workers in north Minneapolis with a sizable concentration of job vacancies in the southwestern suburbs. It also can be a magnet for young workers, eager to locate in urban settings where car ownership is not required. And it can help this region do its part to reduce climate-altering carbon emissions.

That said, the option remaining for fitting the final $144.5 million piece into the $1.9 billion Southwest puzzle is far from optimal. As Metropolitan Council chair Adam Duininck said at Thursday's gubernatorial summit on the transit funding dilemma created by legislative inaction, "The only options available to us are bad options."

The choice the DFL governor endorsed involves the Hennepin County Regional Railroad Authority committing another $20 million; the five (soon to be four) metro counties of the Counties Transit Improvement Board (CTIB) adding another $20 million from already sorely stretched sales tax proceeds, and the Metropolitan Council issuing high-interest bonds known as certificates of participation for the remaining $103.5 million. Each of those entities must approve those moves, and do so quickly. If the project's final $144.5 million funding hole is not plugged by Aug. 31, Duininck said, layoff notices will be issued to the project's 45 employees.

Each of those moves is less than desirable. It's unfair to Hennepin County property taxpayers, and it robs other transit projects in the queue and adds to CTIB's financial distress. It also gouges a hole in already insufficient Metro Transit operating funds.

This funding approach is also fraught with political peril. Republican legislators voiced outrage at the move, saying it breaks faith with assurances Duininck made a year ago that certificates of participation, which do not require legislative approval, would not be used for Southwest. ("I overruled him," Dayton said.) Republicans complain that the project is too expensive and that it would do too little to relieve traffic congestion.

Republicans are signaling that they plan to turn this fall's legislative elections into a referendum on what they maintain is a rail transit boondoggle. That's a regrettable decision that could have far-reaching implications. A GOP election victory on that basis would provide political license to starve Metro Transit and scuttle other transit lines on the region's drawing board.

What's more, it would deepen a worrisome political rift that has opened in recent years between the metro area and Greater Minnesota. That split is already contributing to state government dysfunction. It's inspiring talk of ending Minnesota's tradition of aggregating public resources at the state level and distributing them on the basis of quantifiable need, for the benefit of the whole state. That tradition applies to much more than transportation. And, ironically, Greater Minnesota has benefited the most from the Minnesota Miracle, and now it's most susceptible to political arguments for its undoing.

That's why we hope GOP criticism of Southwest is countered by full-throated support for the project, particularly from the business community. Business organizations were out in force Thursday at the governor's summit urging that the Southwest line go forward. They ought not fall silent in the next two months.