If Trump does not deliver on his promises (like building the wall along the Mexican border, deporting millions of illegal immigrants in this country, create millions of jobs for American citizens, repeal and replace Obamacare), I expect his supporters to turn on him, but apart from that, nothing can be done since he will be president for the next four years. The people can then decide to elect a different president if they choose in the 2020 Presidential election. I personally think that Trump will fulfill most of his campaign promises, such as building that wall to stop illegals from entering America, but will not be able to get Mexico to pay for it.