One of the enduring hallmarks of American Democracy is the peaceful and seamless transition when one president leaves office and the newly elected president is inaugurated. This often occurs within the context of a change in the political party taking control of the reins of government. Much of the world marvels at how this occurs without vitriol and violence.
The danger of Trump's candidacy is that he and his followers/supporters threaten the stability of the peaceful transition. Trump has rejuvenated and retrofitted the old racist and bigoted paradigms with new desire and willingness to openly, and sometimes violently, express white privilege and primacy without regard to political process or social constraint.
If and when they lose, they are prepared and willing to pick up the torches and pitchforks and storm the citadel ranting and chanting their mantra of build the wall, America first etc....
The inauguration of 2017 will be quite different from past ceremonies where the presence of police and military personnel in riot gear was totally unnecessary.