A relevant post from the pit thread on the Trump admin:
http://boards.straightdope.com/sdmb/showpost.php?p=21817742&postcount=35675
In case anyone else is confused why “No, he’s just not going to get Greenland” isn’t an option listed.
Anyways, I’m going with option D: “Trump is crazy but he’s not about to declare war on the EU over a random pronouncement like this”. And I will gladly take bets on that. 
This. And of those the most likely outcome is 1.
No he won’t. No “giving in” will happen either.
This is a distraction, at best. His meme with the hotel was a literal shitpost.
He’s trolling, y’all.
I am HIGHLY suspicious that he didn’t want to go to Denmark for whatever reason, and cooked this Greenland thing up to use Denmark’s refusal as an excuse not to go.
I saw something about how Obama is going to Denmark in September, and he didn’t want to expose himself to the accusation that Obama was going to draw bigger crowds and a friendlier audience than he would.
Obama should negotiate the purchase of Greenland, and then Trump would have to sell it back as part of his anti-Obama presidency.
Well, that makes sense.
Here we go, I found it:
https://www.washingtonpost.com/opinions/2019/08/21/trump-just-nixed-denmark-trip-does-he-fear-contrast-with-obama/
It’s behind a paywall though.
The path goes like this:
Just like that time he repealed ACA and replaced it with much better healthcare!
I didn’t vote since my answer wasn’t an option.
This. I couldn’t vote for either of the no reasons, as they are both wrong as well. Basically, the answer is no…and he probably never intended anything towards Greenland in the first place. It was just Trump being the chaotic mess that he is, and saying some random shit to see what kind of attention he’d get and how folks would react, so that he could see what he wanted to say next to react to their reaction. It didn’t mean anything, just like most of what he says.
I saw a great quote on this earlier. To paraphrase, he’s not playing 3-dimensional chess because, basically, he’s not playing any chess at all and neither knows nor cares what the rules of chess are. He’s just throwing shit at a wall to see what sticks and also to see what he should talk about next based on the patterns the shit makes on the wall. And, ironically, people fall for this every time. I note, with no little irony, that there are multiple threads on the 'dope talking about Greenland as if this were a real thing and as if Trump were really serious about it (or anything else). Good grief, he’s the biggest troll in history! He should be banned from the 'dope. 
I totally forgot about this and I have not seen or heard a word on this since he mentioned it months ago.
Do you think it is all being done so high up in space that we cannot see what progress has been made?
If Trump was hosting a radio show and saying these crazy things, we could just ignore him. But God help us all, he’s the actual President of the United States. Which means we need to pay attention when he says something crazy.
Yes, exactly. When people, including the media, go on and on analyzing what Trump does as if it were some kind of grand scheme they just play into his dog-and-pony show. He doesn’t know what the fuck he’s doing, so instead he just puts on an act. It’s so obvious from how he talks that he’s always just pulling things out of his ass as he goes, hoping it will get a reaction. Why do they think he’s always answering reporters’ questions with things like, “We’ll see,” or “We’re looking into that,” etc? It’s because he didn’t see anything about it on Fox News, so he’s totally clueless.
If the media had any self-respect they would just stop asking him questions and ignore him. It doesn’t matter that he’s president. Just talk to someone else in the administration, and let the attention whore starve.
Well, at least Obamacare got repealed and replaced with “something terrific”, and Hillary is in jail where she belongs. Oh, wait.
Fortunately the US does possess a sort of semi-functional government, and it won’t let the toddler-in-chief start a war with a NATO ally over his temporary infatuation with a shiny toy, even if said toddler throws a tantrum. This is the kind of insanity where the chain of command breaks down and that the 25th Amendment and the power of impeachment were created for.
“Would we annex Greenland? That’s a good question, and it’s one that should be asked. So I’ve appointed a committee to look into that very question, and it will report to me soon, and we’ll know better about our course of action then.”
It’s a nice way to deflect unwanted questions, and has been used by politicians since forever (I’d guess), but Mr. Trump is no politician and he’s not that smart.
You want something “realistic”.
With Donald Trump?
Absolutely this! He’s just trolling the media, so he can point and laugh at how gullible they(we) are. And the lame-ass media have swallowed the bait, hook, and leader. They must take a huge chunk of the responsibility for the clustershit that we’re all mired in these days. But they’re so focused on the profits, that they won’t.
More seriously, his administration is probably doing some super-evil stuff while we’re all looking north.
Like, don’t get me wrong, this would be cute and funny… But at the same time he’s canceling diplomatic appointments and pissing off longtime allies for the sake of, apparently, nothing. We can talk all we want about how he’s “trolling” but the sheer fact that he’s the president means we necessarily have to take what he says seriously on some level, because when your crazy racist uncle you should have disowned years ago says “We should buy greenland”, the response is, “That’s cute, have some more peas Uncle Gingrich”, and when the president says it, the response is, “is he serious, and is he about to ruin our image on the world stage again?”
Now, in an even remotely reasonable society, this would have been one of a dozen reasons to remove Trump from office immediately. We are not a sane society.
And people say there are no stupid questions
Oh wait a sec, nobody ever said there are no stupid polls. I withdraw my comment.