Isn't there a federal program that bails out defunct pension plans at a discounted rate? If GM had gone bankrupt the taxpayer would have been liable to provide some assistance to the bankrupt pension plans. So the 5 billion or so giveaway to the unions by the feds was probably what they would have owed either way.
Now the out and out theft from the bond holders and maybe the stockholders if anything was left was absolutely criminal and the next republican administration should revisit this abomination.
I understand what you're saying, but remember that they split GM into two companies - the one that had an IPO today, and the other one that was riddled with debt. The US taxpayer assumed that company and it's debt. That wasn't $5 billion, that was something well north of $50B. They'll recoup some of that today, and in the future, but they wont' recoup all of it, ever.
Essentially, the US taxpayer is eating whatever is left, plus the $5B (is it a little more than that?) equity stake. I'd have to do the math on paper, but I'm pretty confident that the way they've done it is costing taxpayers much more than any exposure they had from pension guarantee programs.
I agree though, this should be - IMHO - investigation number one when the gavel falls on the new Congress.