Long, tortured efforts to improve Twin Cities mass transit have come to a precarious pass. The next two legs of a planned metrowide rapid transit system — the Southwest light-rail line from downtown Minneapolis to Eden Prairie and the Orange Line bus rapid transit from Minneapolis to Burnsville — are now both in peril, threatened by insufficient state and/or local funding and no small measure of self-serving politics.

With deadlines just ahead for matching more than $1 billion in proffered federal funds for transit construction and one of the projects — Southwest — already seeing costs rise $1 million a week due to delay, it’s time to sound a civic alarm. The prospect of the collapse of the next two transit projects in the Metro Transit planning queue should rouse a more vigorous response from this region’s leaders, in both the public and private sectors. These projects are too important to the Twin Cities’ future growth and prosperity to be cast aside.

Here’s the status of the two proposed lines:

• Southwest’s bid for $900 million in federal matching funds remains incomplete without a commitment of $135 million sought from the state of Minnesota — a sum that also could come from a local or metrowide source. But the Legislature’s House Republicans are so opposed to light rail that they opted to scuttle one of the year’s biggest bills in the final minutes of the 2016 session rather than grant Hennepin County an increase in its debt ceiling so that it could borrow the needed funds.

The House GOP position is unreasonable. But, to date, it is also unyielding. County and Metropolitan Council leaders have been scrambling all summer in search of alternatives that don’t require legislative action. None of them is pretty, but one may be plausible: At Gov. Mark Dayton’s direction and with some additional source of ongoing operating funds for Metro Transit, the Metropolitan Council could borrow some or all of the $135 million by issuing “certificates of participation.” Those are notes that carry a promise of repayment with an interest rate higher than traditional general-obligation government bonds offer.

Certificates of participation for Southwest were rejected a year ago by Metropolitan Council Chair Adam Duininck, who preferred to seek the political comfort of GOP approval for the project. If that comfort cannot be obtained in a special session of the Legislature this summer, Duininck’s 2015 decision should be re-examined.

• The $150 million Orange Line is under two financial clouds. The Legislature’s failure to enact a bonding bill has hung up a hoped-for $12.5 million for the project. And last month’s decision by Dakota County to withdraw from the five-county Counties Transit Improvement Board (CTIB) in 2019 will shrink the board’s annual revenue by 12 percent, producing a deficit. One option for staying in the black, CTIB Chair Peter McLaughlin of Hennepin County said last week, would be to cancel transit improvements that serve Dakota County, including $45 million that the CTIB is expected to contribute to the Orange Line.

Coming just weeks before a Sept. 2 deadline for an application for federal matching funds, a withdrawal of the CTIB’s contribution would be a major blow to a project that has been in the works for more than 15 years and is deemed critical to maintaining mobility in the busiest stretch of freeway in the Upper Midwest. The Orange Line is integral to a multiyear Interstate 35W reconstruction project scheduled to start next year. Even a few months’ delay this year could add an additional year or more to needed work on a roadway now more than a half-century old.

McLaughlin was promptly accused of issuing a punitive threat. But an examination of the CTIB’s financial forecast indicates that its capacity to pay for the rapid transit network that’s been planned for the Twin Cities is already sorely stretched. That’s why Dayton and other transit boosters — including the Star Tribune Editorial Board — have long been calling for a boost to the transit-dedicated metro sales tax from its current 0.25 percent rate to 0.5 percent or more.

That plea and most others relating to Metro Transit have been rebuffed by Republicans, who won a House majority in 2014 by accusing DFLers of being “metro-centric” and seem ready to reprise that theme this year. They fail to recognize that the economic health of the metro area is crucial to the whole state’s success and that transit is a critical component of metro vitality.

That failure of vision cannot be permitted to choke Twin Cities growth. Minnesota leaders who understand transit’s importance need to speak and act now. McLaughlin ranks among them. He has offered to meet with Dakota County Board members to discuss options for keeping the CTIB in the black and the Orange Line on schedule. We hope he is met across the table by elected officials who understand that Minnesota’s 21st-century success depends on willingness to aggregate resources for the common good — just as it always has.