Why did Trump fall out with Bannon in 2017?
[Why did Trump fall out with Bannon in 2017?]
But it was clear from the beginning that Trump was starting move away from what he campaigned on. The disastrous 2018 mid-terms smacked Trump upside the head and got him back on the straight and narrow. That was when the real work on eliminating DACA and building the wall began.
I think Trump would have been better situated if he really had eliminated DACA on day one and required wall funding in exchange for the tax cut legislation Paul Ryan wanted. Instead, he dithered, and Biden is now president. Still, he did really well, considering the disastrous election outcomes for incumbent parties from comparable elections in 1920 and 1932.