"...but I voted with George W. Bush more than 90% of the time."

maverick: A masterless person; one who is roving and casual; an
independent person; an individualist; applied spec. in the U.S. to a
politician who will not affiliate with a regular political party. Also
attrib. in sense ‘independent, unattached’.

But who votes more than 90% of the time with his president and party.