A comparison can definitely be made, I think, in that both the president and the emperor made notable efforts to support Christianity, its adherents and its morality in their respective realms, while at the same time not leading particularly Christian lives themselves—or so it might appear. I cannot judge the president's heart (nor can I the emperor's), and I'm certainly guilty of heinous sins myself. But his administration gears more towards Christian morality than any other government in the West—even if only for its stance on the sanctity of life.
I used to resent President Trump's character, if I'm being honest, and despised his lack of civility. But in hindsight, my thinking wasn't quite independent, was influenced by what I was consuming online, and was not at all informed by my faith. I now see that his moral character really is secondary to the governance of his country and the moral climate it engenders. For all his flaws, he is truly the most pro-life president the States have seen and—in an age where genuine Christianity is something of a religio illicita—as Constantinian a president as we'll ever get.