The liberal group Campaign to Defend the Constitution says it is outrageous for a nationally respected political leader to do anything co-sponsored by a group with an explicit anti-science agenda, ABC News reports.
The event in question is a luncheon in Seattle formally hosted by the CityClub of Seattle and the Seattle World Affairs Council.
One of the nine organizations "co-presenting" the Friday event, but not providing funding, is the Discovery Institute that promotes the theory of intelligent design.
A spokesman for the Republican presidential hopeful pooh-poohed the idea of a controversy.
"He's addressing the Seattle World Affairs Council and CityClub of Seattle and there are a number of co-presenters as well, of which the Discovery Institute is one," says spokesman Brian Jones of the senator's exploratory committee.
Jones adds that McCain's speech to the group focuses on foreign, not domestic, affairs.