Apparently Jeb Bush didn't get that memo. Here's a video the Jeb! campaign released yesterday.
In just over a minute, it goes after Trump on his immigration proposal from the left for his plan to "deport 'em all," and then from the right for critiquing Mitt Romney's idea about "self deportation." That's a pretty direct hit on the number one issue that has come to define Trump's candidacy.
But then yesterday Bush had another gaffe moment that drew all of the attention away from this message. During a press conference in the border town of McAllen, TX, he got pretty testy when asked about his use of the term "anchor babies" and said that - rather than applying to Mexicans - it's more of a problem with Asian immigrants. That created another scenario that he is likely to be answering questions about for the next few days.
Perhaps it is still early enough in this campaign that these stumbles indicate a steep learning curve and Jeb will eventually get his footing. But if he really does want to take on Donald Trump directly, this is certainly not how that's done.