The reality of the 2016 race for second-tier-and-below candidates like Perry is that Trump is soaking up lots and lots of the available oxygen in the race right now. And, they badly need that oxygen. The key for anyone not named "Bush", "Rubio", "Walker" or "Cruz" at this point in the race is to find a way to get attention from the media, from donors and from activists. That's been true in politics forever but is even more the case in a very crowded field with 15 or 16 other people in the running.
Trump's prominence makes that task impossible. He is, literally, everywhere. So, the best chance for a guy like Perry is to go after Trump hard -- in hopes that The Donald responds, which he will almost certainly do. Perry then has to hope the skirmish turns out well for him and that it helps lead to the long-term disqualifying of Trump as a candidate.
It's not just Perry who is trying these strategic tactic of "punching up" to Trump. (It's amazing that a former governor of Texas attacking Trump is punching up. But it is. And politics is weird.) South Carolina Sen. Lindsey Graham, who, like Perry, continues to lag in the also-ran category, said this of Trump on the "Today" show: "We live in the most complicated dangerous times in the world, and he's a wrecking ball when it comes to policy. And the way he's engaged the public is hurting the Republican Party at a time when we have a chance to do better."
Need more evidence of the punch up strategy on Trump? Notice who ISN'T saying much -- or much negative -- about him: Scott Walker and Ted Cruz. Here's Walker in New Hampshire today courtesy of WaPo's Jenna Johnson: "Donald Trump can speak for himself, and I'm not going to put words in the mouth of any candidate, him or anybody else out there." And here's Cruz during a "Meet the Press" interview: "I like Donald Trump. He's bold. he's brash."
Not exactly the sort of denunciations coming from Perry or Graham, right? What's the difference? Cruz and Walker sit above Trump in the first tier of candidates -- and therefore are worried less about discrediting him than swooping in to seize his voters (such as they are) when he flames out.
In short: Expect plenty more jabs thrown at Trump from the Perrys and Grahams of the race. The more Trump fights back, the better it is for them.