The final product — a withering spot that tied Huckabee to a 2003 murder committed by a serial rapist who was paroled while he was governor of Arkansas — never saw the light of day. But the unaired ad, obtained this week by BuzzFeed News, highlights a potentially potent line of attack on Huckabee as he considers a 2016 bid for the presidency.

The ad’s existence was first reported in the 2012 book The Real Romney (and noted, then, by BuzzFeed News). The book’s authors report that Alex Castellanos, then the Romney campaign’s chief strategist, was aiming for an emotionally hard-hitting commercial that would have the same effect as the infamous “Willie Horton” attack ad on 1988 Democratic presidential candidate Michael Dukakis.

Others in the campaign, including Stuart Stevens, believed going after Huckabee so harshly would backfire. The operatives ultimately deferred to Romney, who spiked the ad, believing it would make him look “desperate.”