Burns was re-elected in 1966 and 1970, each time with a different lieutenant governor as his running mate. In 1966, he was elected governor with Lieutenant Governor Thomas Gill. During his term as lieutenant governor, Gill, considered outspoken and acerbic, developed differences with Burns, and was never shy about criticizing the incumbent, despite being part of his administration. In 1970, Gill challenged Burns in the Democratic primary. Gill ran as a reformer, campaigning against what he described as an entrenched, corrupt political machine. He narrowly lost, even though Burns significantly outspent him in a savvy campaign that included sophisticated use of expensive image-building television spots. Most in the state's large Japanese population remained loyal to Burns, who had spearheaded their rise to political power during the 1950s. Before Neil Abercrombie lost in 2014 this race stood as the closest anyone came to a primary defeat of an incumbent governor of Hawaii. Burns' running-mate in 1970, George Ariyoshi, ran to succeed Burns as governor in 1974, defeating Gill in the Democratic primary.