Nationalizing General Motors, and part of Chrysler, may or may not turn out to be a good deal for the taxpayers. I have a different concern, though: Was it constitutional?
No, it was (and is) not. Nowhere in the Constitution is Congress or the President given the power (or authority) to give taxpayer funds to any private institution nor is there any authority for Congress or the President to take control of any private institution.
But, the politicians stopped following the Constitution over 150 years ago so why should we expect them to follow it now?
The Constitution is only used by Congress or the President when it is convenient and can enhance the power and scope of the Federal government. Other than that, Congress and the President run off copies to use as toilet paper.