Yes, some parts of the judicial system of the US are still functioning (see Garcia), however the judicial system is rotting from the top already, the legislative system has been completely paralysed by the Conservative Party in support of the executive. Trump cannot do anything he wants, yet (the Fed is not yet gleichgeschaltet and maybe will be spared, given how dangerous it is to compromise it for the stability of the regime). But he is chipping away safeguards and rule of law at record speed. The US is really resembling in a way the late stage Weimar Republic, also regarding how citizen's still can't imagine the collapse of rule of law and democratic principles, while standing right in front of the cliff, or already one step beyond.

In that regard, it is interesting to note that in Germany, the were two kind of regimes working side by side for a long time. One that still resembled a system of rule of law, for the larger society, that was compliant and not targeted by the regime, and then one that was directed at the opponents or those targeted by the regime, that was completely arbitrary. Supporters but even those not on the bad side, still experienced a rule of law based society and could not even imagine how the reality was already for those that were targeted.

Trump has already ICE, as his SA equivalent. What he still misses is that the court system at the lower levels is still sticking to the law. This will take some more time of corrosive rulings from the top, "unitary executive" and such.