Pataki had often been mentioned as a possible presidential candidate. In early 2015, he began exploring a candidacy for the Republican nomination for President of the United States in 2016, and announced his candidacy on May 28, 2015. On December 29, 2015, Pataki announced that he would be ending his Presidential campaign. A few days later, he announced his support for Marco Rubio for president. After Rubio dropped out and days before the New York primary, Pataki endorsed Ohio governor John Kasich for the nomination.