The beginning of the end for "you and me"

A lot of grammarians are shocked to hear people nowadays say something like "The president is giving a speech, and it is important for you and I to listen," or "It's like he's talking to you and I!" or "Between you and I, this speech is not his best." People have forgotten that the word "me" can be used after the words "you and" - and it seems like we had just gotten people to stop using "you and me" in the subjective case! So where did this come from? House of Pain's 1992 hit song will now play in your head to give you instructions on how to find out.
It all started in the days when people would say things like "You and me gonna go fishin'." Then a grammarian would hop out of the bushes and say. "Halt!" (or alternatively, "Slow your roll"), "Don't you know that you are using that pronoun incorrectly?" Then, in about five minutes of strong didactic gusts that are all Greek to the listener, the grammarian attempts either to set the yokel straight, or to appear very intelligent, with dubious success in the latter, and certain failure in the former. Then the yokel asks what he should say, and the grammarian replies, "Just say 'you and I.' "

You may think that you have inferred the rest of the story, but just wait: it gets worse. What if some poor rube is asked "Who is going to unhitch the trailer?" and responds with "You and me"? Then, in a puff of sulfuric smoke, appears the slightly mustachioed grammarian marm. "You and I," she says, acidly. "I don't think so," the rube responds, thinking he was propositioned. "No, the correct phrase is 'You and I,' " she says, and continues to explain pronouns, subjects, objects of the preposition, and the importance of correct speech. Despite his desire to appear smarter, the rube is decidedly not, and what he hears is this: "No, the correct phrase is 'You and I.' Grom, grom, grom. Blonkshuation... dorp... blonkrammar... floop... blonktelligence. Harankaroo." In this case, all context is lost. The yokel above may have believed that it is "You and I" at the beginning of a sentence, and still believed in "you and me" for the middle or end of a sentence. That's not perfect, but it will steer you right most of the time. In this latter case, the rube, in all likelihood, leaves thinking that every second person-first person compound pronoun is "You and I."

The rube then goes about saying "You and I" for cases both subjective and objective, and through ignorance creep, it gradually moves up the educational ranks, from rube to yokel; yokel to yokel's children; yokel's children to businessmen; businessmen to educated people's children (who are not infected, but, through social media, are carriers); and then to the rest of the world, until it stops dead in its tracks at the foot of the grammarian, who is appalled, and has no idea how such a construction could have entered the world, where ten years before, if anyone had been ignorant (and it had been mainly rubes, yokels, and innocent children who were ignorant), he would have said "you and me" and let the grammarians sort it out. Now, newscasters, politicians, and preachers are using "you and I" in the objective case, seemingly confident that they've sorted out the grammatical nuances of compound pronouns. If anything hurts the ears of a grammarian more than "You and me goin' fishin'," it's "Come fishin' with he and I." The hurting continues, irregardless of the grammarians' feelings.