He's full of it.
By his own words, he had Cruz' eligibility checked out by his own lawyers, who, one assumes, are the best in the business. Fair enough, the guy is in it to win - or better be - but he then said there was nothing there.
So lawsuit now? Ha, right. He'd not waste his own money, enough Dems are stupid enough to waste theirs on the cheese he set out.
Trump certainly learned SOMETHING from Her Thighness.