Like I posted below, Article VII of the Outer Space Treaty of 1967 makes the launching nation responsible for any damages in the event of an accident. As it stands, a private company could launch a rocket but if it does any damage, the country where the launch took place is liable. Of course, when the treaty was written, there weren't any private companies launching rockets.

If the nation is liable for damages, then they should have at least some say in what gets launched. Of course, they'd almost certainly turn around and go after the private company and/or the company's insurance company, but in the event the damages exceeded the insurance or the company's assets, the government would be left holding the bag (of course, I mean the taxpayers).