This column by Henry Olsen seems right to me:
The closing line is the key to the ad’s effectiveness. It turns Trump’s biggest negative — himself — into a positive. Yes, he’s a (insert derogatory term here), but he’s our (derogatory term). His blunt toughness, the campaign will argue, is exactly what the country needs as he forces Washington to change against its will. Conservative writer Victor Davis Hanson has been making this argument for years, analogizing Trump to the gunfighter in a movie Western who the town knows is unsavory but who has the tools to clean it up. The fact that the campaign is now making it shows that staffers know they need to make lemonade out of the lemons Trump has given them.
Olsen goes on to note that the message acknowledges Trump’s flaws, albeit “obliquely.” Whether Trump will be able to stick with it is an open question.