What is the point where “enough of a touch” becomes sufficient to avoid a foul?
Usually if they have diverted the ball enough away from the attacker BEFORE the foul is committed. The one we had where the ref decided to stick with his decision (was that Palace?) and a similar one against the unwashed years earlier show that, where both defenders slid in, essentially tickled the ball but didn't do enough to divert the path or play it to their keeper and then bought our player down. Of course that is assuming the player hasn't gone in recklessly (Studs showing and really high) in which case a "touch" isn't always going to save the player. But ultimately, it is always going to be subjective to the ref on the day, his angle of view, whether VAR can become involved in the decision (goal, pen, sending off) and, as pointed out by Pat, the teams involved. (Although surely Arse trumps Newcastle in the order of decisiosns).