We know that the Donald was registered Republican beginning sometime in the 1980s. I am not aware that we know his registration prior to that. But we do know that he and his father were in close with the Brooklyn Democratic Party and, in particular, Mayor Abraham Beame. This is how I have him meandering D to R to I to D and then back to R.
His record of political contributions to RINOs like Charlie Crist, Arlen Specter, and John McCain along with those to detestable Democrats like Harry Reid, Chuch Schumer, and Charles Rangel plus making the Democratic Senatorial Campaign Committee his largest committee contribution tell me all I need to know about the Donald.