Mitt Romney put the estate tax at the center of a wide-ranging attack on presidential rival Barack Obama's agriculture policy during a campaign rally at a century farm here Tuesday afternoon, accusing Obama of seeking to increase taxes in an area where he'd prefer to eliminate them altogether. But farm economy experts call the tax, assessed on the transfer of property upon death and derisively referred to as the “death tax” by Republicans, a minor issue for the vast majority of Iowa's farming operations. Romney, the GOP presidential nominee and former governor of Massachusetts, called for the estate tax's outright repeal, a position that contrasts sharply with the incumbent Democrat's proposal to raise rates and lower the threshold at which they kick in. “He has a plan for the death tax: He's planning to raise the death tax pretty significantly,” Romney told a cheering crowd of more than 1,200 at a family farm in northern Madison County. “My own view is we ought to kill the death tax. You paid for that farm once. You shouldn't have to pay for it again.” The estate tax has been a perennial political issue and long-loathed by Republicans, but has taken on more immediacy this year as the looming expiration of George W. Bush-era tax cuts threatens to push it to a level that could catch middle-class small business owners and family farmers. Currently, the estate tax is levied at a 35 percent rate and exempted on property worth less than $5.12 million for individuals. But starting Jan. 1, that exemption is scheduled to drop to $1 million, while the rate will rise to 55 percent.