Much has been written about the new Donald Trump, likely shaped by his new campaign manager Kellyanne Conway. Gone are the bombast and the insults. Instead, we see a Trump who is just as aggressive, but more focused, with just a touch of humility and compassion. By some accounts, Trump 2.0 is starting to become more attractive than the original version and is closing the gap with Hillary Clinton. But Trump needs to make a final step for the sake of party unity. He needs to apologize personally to Ted Cruz and his family.

Trump was at his most appalling when he insulted Cruz’s wife Heidi and suggested that his father, Rafael Cruz, was somehow involved in the Kennedy assassination.

The abuses, in turn, elicited Cruz’s full fury and his non-endorsement speech at the Republican National Convention. Cruz’s reaction, in turn, has caused a backlash against the Texas senator and talk of seeing him primaried in 2018.

If Trump is serious about becoming president, he is going to have to realize that he needs allies more than he needs enemies. Cruz can be a powerful ally, if only Trump can go the rest of the way from “expressing regret” for causing “personal pain.” He needs to place a call to Cruz (and pray to God he takes it) and apologize as sincerely as he can manage. Ideally, Ms. Cruz and the elder Cruz should be in on the call.

Trump should specifically not ask for Cruz’s endorsement, which would seem too much like a quid pro quo.

The idea is that the senator would come to that conclusion on his own – or not – depending on how much he would like to forgive and how much he judges it to be to his political advantage.

In any case, Trump should repeat the apology at the next public event. Such a display will surely give the media something to talk about and will put Cruz on the spot.

Cruz is a gentleman and a devout Christian. To be consistent, he will have to accept Trump’s apology, unless he thinks it is insincere and calculating, and go on from there. At that point, an endorsement would seem to be almost mandatory