It's official. The Interstate 35W bridge fell -- not because of what Tim Pawlenty or Carol Molnau did or didn't do -- but because engineers failed to calculate correctly the thickness of gusset plates more than 40 years ago.

The National Transportation Safety Board's findings, released on Nov. 14, must feel like some vindication to Pawlenty, Molnau and MnDOT's bridge inspection and maintenance team.

After the collapse, Pawlenty counseled patience. He urged Minnesotans to wait for a thorough investigation before leaping to conclusions about why the bridge fell.

Instead, critics launched a relentless -- if often subtly expressed -- search for villains to blame for what we now know was a tragic accident.

Sometimes bluntly, sometimes not, critics suggested that Pawlenty's skinflint tax policies and budgets had set the stage for the I-35W bridge tragedy. The governor's opponents maintained that he had sacrificed bridge maintenance and safety -- and thus the well-being of Minnesotans -- in an attempt to adhere to his no new taxes pledge.

Sen. Jim Carlson, DFL-Eagan, vice chairman of the Senate Transportation Committee, put it this way after the NTSB issued its report. While Pawlenty "didn't cause [the bridge] to go down," he said, the evidence shows that "very few did something to keep it up." The governor, Carlson added, "really ought to be lowering his head and saying, 'I'm sorry.'"

Molnau was the target of particularly vicious condemnation. Critics painted her as an incompetent clown who blithely superintended a bridge inspection and maintenance program that was shoddy, irresponsible and done on the cheap.

Even the respected NTSB got a moral dressing-down when its actions displeased DFLers. Some suggested that the NTSB's leaders might be shielding Pawlenty and so couldn't be trusted to carry out an impartial investigation. In January, when the agency released its interim findings, Sen. Steve Murphy, DFL-Red Wing, chairman of the Senate Transportation Committee, told the Pioneer Press that the NTSB's report was "not worth the paper it's printed on."

DFL legislators claimed the moral high ground for their own policy prescriptions. After the bridge fell, they pushed through one of the largest tax increases in state history, which included higher gas taxes and a massive increase in transportation funding. They justified it as a moral imperative.

At the national level, Eighth District Rep. Jim Oberstar took a similarly sanctimonious tone when he called for a "temporary" 5-cent increase in the federal gas tax for a national bridge repair "trust fund."

"If you're not prepared to invest another five cents in bridge reconstruction and road reconstruction, then God help you," proclaimed Oberstar, chairman of the U.S. House Transportation and Infrastructure Committee.

Minnesota DFL chair Brian Melendez also used moral language to denounce Rep. Michele Bachmann and Rep. John Kline after they voted against the massive federal road spending bill that included money to rebuild the I-35W bridge. "This goes beyond ridiculous. It's callous," he huffed.

Never mind that Bachmann and Kline favored the I-35W bridge appropriation, but opposed the transportation bill because it was stuffed with wasteful pork-barrel projects.

To their credit, Minnesotans didn't buy this moral posturing. After the bridge collapse, Pawlenty's approval rating in opinion polls was the highest it had been since he took office. And despite DFL finger-wagging, a majority of Minnesotans opposed a state gas-tax increase.

What precipitated this search for villains, before any of us had a clue why the bridge had fallen? Clearly, DFLers hoped to reap a political windfall from the tragedy. But something more fundamental was also at work.

Today, we can't accept that some calamities are accidents, or "acts of God." We operate within a culture of blame, which holds that if something goes wrong, someone must be responsible.

Our litigious culture encourages this view. It insists that when a bad thing happens, a guilty party must always pay.

Unfortunately, this culture of blame is misguided and destructive. It only whips up ill will, foments distrust and ensures that a disaster's tragic effects will linger.

The NTSB findings confirm that those who rushed to identify devils in the I-35W bridge disaster acted shamefully. Before we move on, we should publicly acknowledge the great injustices done.

Katherine Kersten • 612-673-1774 Join the conversation at my blog,