Trump effed up the president’s power over immigration issues with his asinine tweets about Muslims, which I didn’t think would happen since border entry is a core executive function, but he did, the courts took the opening, and those rulings are still there. So yeah, I think there’s a non-negligible chance that Trump screwed the pooch on this one too with his jackassed tweeting.
Oh, it's more than a non-negligible chance that Trump has hurt the Administration's legal position with his tweets. The courts have provided him far less leeway on his proposals to bar travel from (some) Muslim-majority countries because they interpreted his tweets as reflecting his bias against Muslims, right or wrong.
With regard to DACA, I'm not sure his tweets have any real relevance, notwithstanding that they were cited by the judge. The court on appeal likely won't address such dicta, but rather the legal principle of detrimental reliance, as noted in my post above.
President Trump frustrates the heck out of me. On matters of policy, he has delivered far more for conservatives than most of us had any hope to believe. But as a head of state, he's been a complete embarrassment.
Keep in mind that the President of the United States has two roles - he is the head of government and the head of state. Those roles are often split between two individuals - in the UK, there's the prime minister who speaks for the government and the queen who speaks for the nation. Trump speaks for our nation, and I cringe every time he tweets about bleeding facelifts and bigger buttons. Yes, I'm old fashioned - my idea of a President embodies such qualities as dignity, decorum and gravitas. And Trump is none of those things. Yes, he is moving the ball forward on issues that are vitally important to me. But his insufferable ego and temperament make me fear that all will be lost the next time the voters have the ability to speak their minds about Republicans and conservatives.
The bright side is that Trump's public meeting with Congressional leaders shows that he can change, or at least that he's enough of an actor that he can appear to change if need be. I hope someone has enough influence with him to convince him that the way ahead - starting right now - is to project a more traditional and capable vision of Presidential leadership.