To expand on what someone asked earlier, why was first term Trump so milquetoast, I will say this.
Trump believed politicians, like the business and media people Trump had worked with his entire life, were motivated and incentivized by money, power, or a job well done. These are tangible and can be transacted upon. Put simply, Trump knew how to grease palms and persuade people with things they want.
However, this only works with rational people who desire rational or at least material things. Trump did not find a system operated by rational actors in Washington DC. He found a quasi religious order that could not be bargained with. Republicans received money from elsewhere and were the closest to a greasy business associate looking for a little action Trump would find. But men like John McCain would throw away all their principles, irrationally, just to spite Trump (McCain campaigned on repealing Obamacare and to spite Trump voted NOT to repeal).
Democrats, also greedy money grubbers, had the religious Jacobinism that made their actions and motives totally incomprehensible to a man like Trump. Trump genuinely believed the system was staffed by rational actors and if you give them a cut of the action, like any business dealing, things can get done.