Re: vagueness on policy.
Yes he is, in the same way that Brexit didn't outline an actual plan. But Leave actively went for issues that were about grievance and deliberately let the voters decide in their own minds what the policy would entail.
Trump regularly talks about doing x to one audience and then doing exactly the opposite y to another. And then denying both at one point or another. But he's got the relevant quote out thats repeated on social media, and in a world which doesn't fact check and only hears what it wants to hear, these contridactions don't matter in an election cycle. The rebuke and the deep dive aren't repeated on social media in the relevant echo chambers - they are only repeated in opposite channels.
Trump tailors his message for each any every audience in this way.
However with regards to immigration, I do note one comment he's made as its notable for us - think about target audiences here.
Trump has said he is looking at Rwanda as an option for these deportations. Its an interesting comment as its absoluetely NOT aimed at Americans but solidly Brits and Germans and other Europeans because its a topic of conversation in European circles not American ones.
This comment demonstrates an understanding/awareness beyond America/an American audience which isn't 'stupid' in the way we perhaps sometimes percieve Trump.
I'd argue this is 'soft power foreign policy' in action. We are likely to see a lot more of it. Its something thats not great for a Labour government in the longer term. Our next election is due the year after the next American one so our election cycle means we will be directly influenced by the next American election cycle (which may well be not as democratic as previous ones). Its something Labour should be thinking about hard. The timing is about as bad as it gets for them.
FWIW, over immigration, I don't think its in Trump's interests to go hard initially in policy making for hispanics who are in work and established in the community - even if their documentation isn't necessarily in order. He'll want the cheapness and optics of being seen to be 'decisive' and 'doing something', rather than costly investment in state clear outs of 'undocumenteds'. Of course how this plays out on the ground with individuals who have grievances against someone hispanic may not be so nice (think about snitches in authoritarian regimes who target anyone they don't like and use the system against them). I don't think Trump will be interested in dirtying his hands by going really heavy handed at first. He will go for easy, cheap wins. And turn a blind eye to less pleasant stuff on the ground stating 'state automony'. He has plenty of followers to do the dirty work for him.
Again the Dems face a dilema here: if they see issues with how illegal migrants are being deported, what do they do? Their only recourse is probably through the courts. But the optics of fundraising to help illegal migrants is problematic in its own right for them now because of identity politics and how the well is now totally poisoned...