Washington -- President Bush portrays his position on Iraq as steady and unwavering as he represents Sen. John Kerry's stance as ambiguous and vacillating.

"Mixed signals are the wrong signals,'' Bush said last week during a campaign stop in Bangor, Maine. "I will continue to lead with clarity, and when I say something, I'll mean what I say.''

Yet, heading into the first presidential debate Thursday, which will focus on foreign affairs, there is much in the public record to suggest that Bush's words on Iraq have evolved -- or, in the parlance his campaign often uses to describe Kerry, flip-flopped.

An examination of more than 150 of Bush's speeches, radio addresses and responses to reporters' questions reveal a steady progression of language, mostly to reflect changing circumstances such as the failure to discover weapons of mass destruction, the lack of ties between Iraq and the al Qaeda terrorist network and the growing violence of Iraqi insurgents.