Keller was a leading supporter of the 2003 invasion of Iraq, explaining his backing for military action in his article 'The I-Can't-Believe-I'm-A-Hawk Club'. Two days after the invasion, Keller wrote the column 'Why Colin Powell Should Go', arguing for US Secretary of State's resignation because his strategy of diplomacy at the UN had failed. In contrast, Keller was much more sympathetic to Deputy Defence Secretary Paul Wolfowitz, describing him as the 'Sunshine Warrior'.