I don't know if we can count on the ACA staying around forever.
And you must be confident that Trump will lose, since the 5-4 majority that saved Obamacare last time will not survive a few more Republican appointments.
https://en.wikipedia.org/wiki/List_of_justices_of_the_Suprem...
That said, many justices have not voted as expected. In other cases political parties have swapped positions on various issues etc.
the 5-4 majority that saved Obamacare last time will not survive a few more Republican appointments
You seem unaware that Chief Justice Roberts authored the opinion upholding ACA.