Then explain Jeb stomping McBride despite a national effort by the Dems. (Hint: You can't)
Jeb did not win because the GOP has a registration edge. He won because of his personal leadership capabilities and McBride's lack thereof, plus the fact that he had a good record, and his brother was the President.
McBride was a poor candidate. He is not the least bit attractive, and has a grating, squeaky voice. People make many of their decisions on who to vote for based on appearance and appeal and McBride had neither.
He also carried the full Democratic Party's Leftist ideas.