Romney took 42 percent in the latest Arizona poll, followed by Rick Santorum at 29 percent, Newt Gingrich at 16 percent and Ron Paul at 8 percent.
Romney held an eight-point lead in the same poll last week.
It’s the latest round of polling conducted after Wednesday night’s Republican debate in Arizona to show Romney pulling away from the field in the two states that will hold their primaries on Feb. 28.
Romney leads by six points in the latest Rasmussen survey of Michigan.
Santorum led the same poll last week by four points, which had many conservatives predicting chaos in the Republican primary if Romney couldn’t win the state where his father was once governor, and where he lived until he was 18.
But Romney and Paul battered Santorum over his record as a senator at the debate, which seems to have boosted Romney heading into next week’s primaries.