For all practical purposes, GM has already failed. It should now be allowed to do so formally.
We must not be afraid of the bankruptcy process. Bankruptcy does not mean liquidation. The process will help the company, not eliminate it. It would give GM the cover to do what it absolutely must: close plants, eliminate unprofitable brands and dealerships, and shed its bloated cost structure. It will enable GM to wipe the slate clean and emerge stronger. Going forward it will be able to compete again, without the inspissating heavy burden of past obligations.
Subsidizing the industry is not going to solve the root of the problem, but will simply mean perpetuating an unproductive structure, which will almost guarantee bigger problems later on. Why should we transfer capital from the successful businesses to the doomed? Throwing taxpayers' good money into that sink hole called the US auto industry will be tantamount to a transfer of wealth from tax payers to GM employees. The capital that will be consumed by GM is needed elsewhere, perhaps for re-training people to make them more employable, and could be used more efficiently if not allocated by Congress or the bureaucrats at Treasury.
In capitalism, the consequences of failing to compete are that you vanish, making way for more efficient organizations. That is how the economy rejuvenates itself.
Let GM fail.