The Republicans seized upon Brown's increasing unpopularity by nominating a well-known and charismatic political outsider, actor and union leader Ronald Reagan. With Richard Nixon and William Knowland working tirelessly behind the scenes and Reagan trumpeting his law-and-order campaign message, Reagan received almost two thirds of the primary vote over George Christopher, the moderate Republican former mayor of San Francisco; his push towards the general election held great momentum. At first, Brown ran a low-key campaign, stating that running the state was his biggest priority, but later began campaigning on the record of his eight years as governor. As Reagan's lead in the polls increased, Brown began to panic and made a serious gaffe when he ran a television commercial in which he reminded a group of school children that an actor (i.e., John Wilkes Booth) had killed Abraham Lincoln—a crude character assassination based on Reagan's work as an actor. The comparison of Reagan to Booth did not go over well, furthering the decline of Brown's campaign.