Romney Closing Gap in Michigan Rick Santorum's 15-point lead shrinks to 4 By Matt Cantor, Newser User Posted Feb 20, 2012 7:19 AM CST 2 comments Comments Former Massachusetts Gov. Mitt Romney speaks in Salt Lake City, Utah, Saturday, Feb. 18, 2012. (AP Photo/Gerald Herbert) (Newser) – Last week, Rick Santorum led Mitt Romney in the Michigan race by 15 points; now, that lead is down to just four points, Public Policy Polling finds. Some 37% of voters say they support Santorum, compared to 33% for Romney; Ron Paul follows with 15%, while Newt Gingrich stands at 10%. It's not that Santorum's performance has declined, pollsters note: It's Romney who has successfully buoyed his campaign, and he's done so by bolstering his image rather than tearing down that of his opponents. His support has grown from 24% last week. And where Santorum's favorability/unfavorability rating has remained at 67/23, Romney has expanded his spread from +10 to +20 points, at 55/35. The former governor also has Newt Gingrich to thank for some of his success: Some 45% of Newt backers would back Santorum if Gingrich dropped out, whereas just 29% would support Romney. That would put Santorum's lead at 42% to 33%. Santorum holds double-digit leads among Protestants, union members, evangelicals, and Tea Partiers; Romney is ahead among women, seniors, moderates, and Catholics.