Will Trumpism die as quickly as it rose assuming Trump loses in 2020?

[Lumine]

Doubtful. Not impossible you could end up hearing "Donald Trump was not a true conservative" at a 2024 or 2028 GOP debate if he experiences an utter electoral meltdown (which seems to be impossible on account of polarization), but he's clearly managed to appeal to a large number of voters which are likely to continue voting for similar - if possibly more "restrained" in terms of personality - candidates.

It bears reminding it wasn't officeholders who legitimized his brand of politics (despite all the criticisms one may have about their less than courageous behavior), it was voters. Barring some sort of seismic shift in terms of their priorities and/or judgment towards Trump and "Trumpism", it stands to reason a sufficient number will still vote for similar candidates and ideas so as to make it a more permanent attitude. Whether that's enough to create a Trumpism without Trump recipe for victory in a future difficult to predict is impossible to say.