He will try and hold on but I think it's inescapable at this point. Mainly bc he will stoop to any level to try and keep power - and this will only annoy/aggravate people even more.
If the day after it emerged he shouldve fessed up saying he admits to having been boorish with women, admits there are probably others that may come out. Follow it by mentioning he was single and unfortunately was thinking with the wrong head (not in those words obviously). Reiterate that when you make that kind of mistake, it will lead to you making otherwise indefensible mistakes like pursuing young chicks. He should've showed some personal vulnerability. Be open about the fact that as a man in his 60s, it's difficult to come to terms with age and that one way ppl with influence try to combat that is by pursuing younger women. He didn't have to be super graphic or anything but most ppl understand this dynamic. And nothing puts people in a forgiving mood more than watching the rich/powerful/influential admit to their lowest but most relatable weaknesses. Finally he should've been clear that he never retaliated in any way (im assuming this is actually true) if the woman rejected his advances. And then try and make a broader point about how men of his generation are oftentimes guilty of this behavior. Then, he should never have tried to control or influence the investigation. Announce he will accept whatever investigation that the AG feels is appropriate, and will cooperate 100% with it. Then finish the statement by saying that while he supports the investigation etc, that ultimately he will leave the decision of whether he will resign to the people. If there is a popular movement/drive for his resignation, he will do so. If he did that, he would be close to 50/50 approval ratings and would be in a position to win back some of the support between now and 2022 (assuming he wants to run for reelection).
