To "learn from Bush" would be to get out of Afghanistan, NOT up the ante. 

"America eventually needs a capable, non-radical government in Afghanistan that controls as much of its own territory as possible. This will not be achieved by bombing the hell out of the Taliban alone. It will also not be achieved without bombing the hell out of the Taliban, since they have no current incentive to come to the peace table."

Gerson is bonkers if he thinks a durable peace is possible in Afghanistan, a country in name only that is really just a collection of tribes, without the Taliban in control. We've already poured billions down that rat hole, with many more to come. To call this idiocy would be a compliment. Trump isn't learning from Bush, he's doing his honest best to be worse.