WASHINGTON — Conservative activists are heaping criticism on Sen. John McCain for fighting President Bush over proposed rules for the interrogation of terrorism suspects, a dispute that has reopened long-standing divisions between the maverick Republican lawmaker and his party's establishment. The attack from the right, which coalesced over the weekend, could undercut McCain's effort to woo Bush backers and other party regulars for an anticipated 2008 presidential bid. His position on terrorism prisoners has fueled critics' skepticism about McCain's conservative credentials. "This very definitely is going to put a chilling effect on the tremendous strides he has made in the...