I asked that question of Elwyn Tinklenberg, who was Jesse Ventura's transportation commissioner (so he knows how this stuff actually works and doesn't) and whom I view as fair-minded (although a Democrat).
He said the issue has to go beyond the question of the blameworthiness of a particular transportation commissioner and governor. He felt that the eight years of the Arne Carlson administration before Ventura came to office had been years of infrastructure neglect. He knew when he was commissioner that roads and bridges needed increasingly urgent attention, but he couldn't get the level of funding necessary to really tackle the job. So he said he "feels some sympathy" with Pawlenty and Molnau, standing there holding the bag when the nightmare became horrible reality.
Tinklenberg makes a good point, but I highlight this passage for another reason. Black finds a source he thinks is honest and knowledgeable. He discloses the most relevant facts that bear on the source's credibility (the source is a Democrat). Finally, Black tells us what the source says.
Black is putting his reputation on the line here, which is good. The journalist should bear some responsibility for what is printed under his or her name. Oftentimes readers are better served by hearing from one expert, properly disclosed, rather than hearing from multiple experts.