But here’s one of the big surprises about the Parnell case, which was brought by Mike Moore, a federal prosecutor in Georgia. Moore relied as much or more on plain old fraud charges as he did on food safety laws, which do allow for individual prosecutions. The fact that the salmonella outbreak caused nine deaths wasn’t even part of the trial. Instead, the focus was on whether Parnell committed fraud by knowingly introducing tainted peanut butter paste into interstate commerce. The fraud conviction is what brought that eye-popping sentence.

There are plenty of people — people who genuinely understand the law — who believe that Bharara could have done the same thing with G.M. executives who knew about the faulty ignition but said nothing to the government, even though they were required to do so within five days of learning about a safety problem. In their view, Bharara’s cautious reading of the law is far too narrow.

“The fraud in the peanut butter case is that it was contaminated and they knew it,” said Clarence Ditlow, who runs the Center for Auto Safety. “What did G.M. executives do? They knowingly sold a defective car.” Rena Steinzor, a law professor and author of “Why Not Jail?,” about the legal consequences of industrial mishaps, said that in the prosecutors’ statement of fact they specifically noted that G.M. was assuring the public that the cars were safe when people inside the company knew they weren’t.

Sen. Richard Blumenthal, a Connecticut Democrat and a former attorney general of that state, has co-authored a bill that would make it easier to prosecute auto executives. But he also had little patience with Bharara’s explanation.

“It’s a crime to make a false statement to the government,” Blumenthal said. “18USC1001,” he added, citing the law. “If you submit a false statement to a federally insured bank in connection with a $500 loan, prosecutors can go after you. G.M.’s false statements are just as much a violation of the law.”

I’ve seen it written recently that the urge to prosecute corporate executives is little more than an exercise is schadenfreude. But it’s not. It is instead the single most powerful deterrent imaginable — far more powerful than a fine, which is meaningless to a company like G.M.

“I guarantee you,” says Blumenthal, “one sentence like [Parnell’s] would change auto safety dramatically and enduringly.”