You know - this will just not end well for Trump. Pelosi knows just exactly how to waterboard him figuratively for MONTHS on end.
This shutdown / wall debate, however it ends, is just a dress rehearsal for the FY2020 and FY2021 Budget battles. Pelosi controls both this debate and those to come by virtue of her office, and the cohesion of her caucus. She will tell both Trump and Mulvaney that their budget drafts are not worthy of consideration, reset the budget priorities for the next decade, and oversee the overseers of Trump’s crimes.
She can drive Trump crazy enough to kill him via stroke, heart attack or dementia. Failing that she is very effectively forcing him into behaviors that will doom his reelection campaign before it starts, risk the forced removal of him from his office, and most certainly guarantee that he will be prosecuted by a future Atty General for multiple felonies and spend the rest of his sorry days incarcerated.
If he was smart he would resign right now and appeal for clemency from VP Pence before he burns every bridge he has left, but we know he is the stupidest human to ever step into the White House, and just maybe the stupidest man on Earth.