So anyone who has ever had a liberal past is not a good candidate?
Ronald Reagan was a lifelong liberal Democrat until 1962 when he became a conservative. Three years later he ran for governor in California.
Cruz is beginning to really irritate me.
Reagan validated his change over time with actions. It was not a sudden change as he began positioning for a presidential run. That is the difference to me. If Trump had a decade of actions to support his change in stance, I would have a different response to his claim.