He would indeed, Hubert Humphrey, Henry Jackson and other pro-America Democrats would either declare themselves Independent, or do a Phil Gramm and just switch parties, except for the fact that the GOPe-RINO Axis is just as disgusting and vulgar as the ‘RATs, which is why Trump continues to surge in the polls.
It's hard to say what Henry Jackson would do if he were still alive, but generally politicians follow the drift of their party.
Hard to believe, say, that Jack Kennedy would have gone against his family and his supporters and switched parties when the Democrats moved left.
After a certain point it may not make much sense to speculate about what Hubert Humphrey would be thinking in his second century of life, but would you really expect him to leave his party behind after so many years? Or would he just follow the same path that Jimmy Carter or Jerry Brown has?
And Phil Gramm? Big supporter and profiteer from illegal immigration. The Democrats can have him.