DUNLAP, Iowa — When Senator Hillary Rodham Clinton’s campaign advisers laid out their new political strategy in a private conference call with allies last Tuesday, Bill Clinton was not on the line. He did not need to be. The message being delivered was his.

The “change, change, change” phrase, as some advisers call it, was coined by Mr. Clinton after he told campaign officials that the old strategy of running like an incumbent front-runner was not enough, advisers said. The Clintons had to wrest the message of change from Senator Barack Obama.

He is shaping strategy, challenging advisers on their assumptions and acting like a vice-presidential candidate in a general election — attacking rivals so Mrs. Clinton can stay positive much of the time.