Unless you happen to fervently believe in a principle itself, and no one ought to, because principles aren’t real, you should never use one to win an argument, because one day something you love will run counter to the principle, and then you will be forced to watch it die. The argument against the Iraq war was that it was a bad war; it should never have been that military intervention is always wrong as a matter of principle. Now we have a relatively non-interventionist President, and the price is the murder of an entire country.