petersen called himself the bernie sanders of the libertarian party due to his grassroots fundraising strategy. after ted cruz terminated his campaign for the republican party's nomination for president, petersen received the backing of mary matalin and erick erickson. in many polls, he placed in the top three presidential choices for his party, along with opponents john mcafee and gary johnson. on may 29, 2016, at the libertarian national convention, petersen lost the nomination to johnson, getting second place on the second ballot. petersen congratulated johnson on the win and gave him a replica of george washington's pistol. petersen then criticized johnson's vice presidential pick bill weld, in response to which johnson placed the replica into a garbage can.