True, I have no right to buy something unless the seller chooses to engage in the transaction with me. What you're discussing is a situation where the government, who isn't a party to the transaction, stepping in and preventing the manufacturer/seller from using those resources, and taking those resources for itself in the name of "national security."
The government seems to be a parasite and an interloper in that instance. Is it the buyer's or seller's fault that the government has gotten itself into a war, and now needs to extract resources (or even citizens in the event of a military draft) from the private sector to go battle another government somewhere? Of course, this is a whole different topic for the purposes of this thread.
Okay, so YOUR point is, that the Constitution, which cedes the RIGHT to protect this nation, to the president, means less, than your own ( or the seller of goods' right to sell them to you ) to buy / own something which is for the common defense. Very interesting; though parasitic, selfish, arrogant, and stupid. Thanks, for this insight, on just how much MORE regard you hold yourself in, than the good of anyone and everyone else. Not to mention, of course, that you think that " the government " gets us into wars. Libertarian, are you ?