Sometimes, it's almost like Mayor Luke Ravenstahl is trying to look like the bad guy. While everyone else in town was celebrating an apparent deal to stave off massive cuts at the Port Authority, Ravenstahl went on record to express concerns about the use of county sales-tax proceeds to shore up the system. Although Ravenstahl didn't express outright opposition to the plan, his trouble brought him condemnation from City Councilor Bill Peduto.

Set aside, for a moment, the political overtones of all this, like the obviously dysfunctional relationship between Ravenstahl and Allegheny County Executive Rich Fitzgerald, who brokered the transit deal. (It is worth mentioning, though, that the relationship between Fitzgerald and Peduto -- who will almost certainly be challenging Ravenstahl's 2013 re-election bid -- is cozy.) There's room for debate on the merits of using proceeds from the county's 1 percent Regional Assets District (RAD) sales tax. See, for example, the Pittsburgh Comet's take on Ravenstahl's concerns; then compare and contrast with Keystone Politics' whole-hearted embrace of the deal.) And as first reported here earlier this week, the use of RAD dollars was naturally received with some trepidation from the art world, which relies heavily on RAD money. Greater Pittsburgh Arts Council head Mitch Swain told me, "I would hope that this wouldn't impact arts funding." He later expressed similar misgivings to the Tribune-Review.

You can't say such fears are groundless.

Yes, as Fitzgerald points out, sales-tax revenues have been on the rise lately. And Swain also told me that even in the worst of the economic downturn, funding from RAD "was surprisingly stable." But years ago, then-Mayor Tom Murphy pushed for the use of RAD dollars to fund the construction of new stadiums for the Pirates and the Steelers. As I wrote a couple years back, the argument at the time was that stadium funding "would not divert money from other regional assets because the RAD pool had been growing steadily. [So] there would be money for everything." Sound familiar?

But a decade later, the Carnegie Libraries discovered that, in fact, there wasn't enough money for everything. The library needed an influx of money to sustain its branch operations -- beyond what it already received from RAD. And it came to city taxpayers with hat in hand -- first for an additional allocation from the city budget, and then with a 2011 referendum for an additional library tax.

The library tax passed overwhelmingly -- no doubt thanks to the support of gifted editorialists -- though Ravenstahl himself, again, had misgivings. For that matter, he's also been accused of foot-dragging on disbursing city money to the libraries.

But whatever you think of Ravenstahl's performance on the library issue, the point remains: He -- and the city -- have arguably been bitten in the ass by multiyear commitments of RAD money before. You can't blame him for being cautious now. (Anyway, given that the county's drink tax was created to shore up transit, should reversing a 2008 reduction of the tax be up for discussion?)

The RAD board will have hearings on the transit-funding proposal, of course, and you can expect the arts community to press for assurances that they won't be hurt. Ravenstahl may back that cause, but at the end of the day, I'll bet my monthly bus pass that this deal will go through. Voiding it could jeopardize the state's promise to provide more than $30 million a year -- which would jeopardize the very transit system itself. That, in turn, would antagonize union workers -- who sacrificed mightily as part of Fitzgerald's bargain -- with Ravenstahl's re-election bid less than a year away. Finally, it would require Ravenstahl to risk public outrage from transit riders themselves -- all for the sake of culture-workers who are probably going to back Peduto anyway.