Not all of them. The Second International is a good dictionary. The Third and its contemporaries came under the influence of the Modernists whose beliefs eventually metamorphosed into post-modernism and the principle that words have no meaning except to construct oppressive relationships. At the popular level the dictionaries ceased to be "prescriptive" and became "descriptive" i.e. they hold that there is nothing correct or incorrect and if Clinton wants to say that sex doesn't mean oral sex, or even the more straightforward kind for that matter, well he is just as correct as the next guy. Insofar as conservatives carry their conservatism over into their language use their arguments will always be superior to those of the Liberals- postmodernists all- even when the Liberals seem to have their facts straight because the words they use will contradict their facts at some point if they speak more than three sentences about the same subject because words, to them, mean only what they want them to mean at the time they speak them and they can use the same words with opposite meanings in the same conversation and think they are being totally consistent and brilliant.
I would hope that a conservative would not allow the Left to determine his language because that gives the argument to the Left because they, with perfect sincerity, will insist that you have said exactly the opposite of the words you used as you understood those words and if you have accepted the Left's linguistic principles they will have the best of the argument because you let them define the words you use and their definitions are always only conditional.
You're assuming that any dictionary author has the authority to ascribe meaning to any given word. Words have meaning not because some single authority says they do, but because the users agree on that meaning. And dictionaries don't create meanings; they simply document them.
Samuel Johnson could define "liberal" as "enlightened," but if we all know it means "vacuous and sophomorically idealistic," then Doctor Johnson's meaning is at best irrelevant, a mere parlor exercise.
ALL dictionaries are therefore "descriptive" rather than "prescriptive" (your terms). And it is no more valid for me to accept your arbitrary devotion to obsolescence than it is for me to let the Left define my terms for me.
I KNOW the meaning I intended when I used the word "decimate." That usage was perfectly in keeping with modern understanding, so my use of it communicated exactly what I wanted it to. That is the value of words. They are not pretty objects to sit on a mantel gathering cobwebs; they are meant to be taken down and used. Sometimes in their use, they acquire a scratch or two. And some just plain wear out. Others wear down but are then refinished and served up anew.