Deepening a rift ahead of the largest annual gathering of conservative activists in Washington this week, some of the movement’s top leaders have circulated a private memo urging that conservatism’s founding principles be recast to exclude gay rights groups from the Reagan coalition of economic, defense and social conservatives. The memo, obtained by The Washington Times, was signed by about two dozen leaders, and was released just as the Conservative Political Action Conference is set to begin its most contentious session in years, riven with divisions over a gay rights Republican group that is helping sponsor the conference and the...