Both former Massachusetts Gov. Mitt Romney and former Pennsylvania Sen. Rick Santorum are focusing on Michigan’s Republican presidential  primary, since a Santorum win in Romney’s home state could kill off any remaining thoughts of inevitability for a Romney nomination.

The latest TIME explains how top Santorum strategist John Brabender is surveying the electoral map.

Brabender is surveying the electoral landscape for ways to vacuum up votes on the cheap. A knockout in Michigan isn’t the only path to victory. Santorum’s team is focusing on conservative states that award delegates proportionally, rewarding a second- or even third-place finisher, and have inexpensive media markets. The strategy has already borne fruit. While Romney and Gingrich dueled in Florida, Santorum barnstormed Minnesota, Missouri and Colorado and snatched race-changing wins in states no one else had considered worth the fight. Now his aides are targeting March 6 Super Tuesday contests in Georgia, Oklahoma, North Dakota, Tennessee and Idaho as chances to win delegates on the cheap, as well as Ohio, another ailing Rust Belt state where Santorum’s profile might trump Romney’s.

That’s why Romney would love to dispatch Santorum in Michigan. Romney won the state comfortably in 2008, and as a self-styled “son of Detroit,” he may have expected another cakewalk this time around. Yet he lags Santorum by an average of 9 points in recent polls. Those numbers were disquieting enough to make Romney dump $1.2 million into advertising in Michigan, including a spot that highlights his local roots with sepia-toned family footage. A rather less sentimental campaign, funded by Romney’s deep-pocketed super PAC, flays Santorum as a “Washington insider” and “big spender” who voted repeatedly to raise the federal debt limit. In response, Santorum, who has spent a fraction as much, unveiled an ad branding Romney a nasty, machine-gunning “Rombo.” Keenly aware that Romney’s unfavorability ratings have spiked in recent weeks, the Santorum camp hopes to provoke a backlash against his negative attacks.

Santorum also aims to drive home doubts about Romney’s ability to connect with average Americans. In a recession-racked industrial state like Michigan, Santorum’s blue collar biography–his grandfather emigrated from Italy to work in the coal mines of southwestern Pennsylvania; both his parents were devout Catholics who worked at a local Veteran’s Administration hospital–stands in sharp contrast to Romney’s tin-eared affluence.