The Heritage report was a reprisal of a study the group released at the height of the last congressional debate on immigration, in 2007, which said the bill being considered then would have cost $2.6 trillion. That figure, too, was disputed, but it carried weight with Republicans and helped lead to the legislation's eventual defeat in the Senate.This time, supporters of the bill are determined not to let opponents wrest control of the debate. Anticipating Heritage's release of its new report, bill supporters responded quickly with conference calls and talking points criticizing its methodology and the foundation's agenda. The Heritage authors acknowledged their report does not attempt to offer a comprehensive analysis of the entire 844-page immigration bill, which would boost border security, change legal immigration and worker programs, require all employers to check their workers' legal status and offer eventual citizenship to the estimated 11 million immigrants already living in the country illegally. Instead, the Heritage study focused almost exclusively on the added costs the government would incur in providing benefits to immigrants here illegally once they gain legal status. These include Social Security, Medicare, unemployment insurance, health care, welfare, public education, and services like police and fire protection, highways and parks. The study said an average adult now living in the U.S. illegally would receive $592,000 more in government benefits over a lifetime than he or she would pay in taxes. "It becomes extraordinarily expensive," the lead author, Robert Rector, said at a press conference near the Capitol for unveiling the report. Costs are higher for this bill than the last one in 2007, Rector said, partly because government spending itself has grown more generous. Heritage is not the only conservative voice opposing the bill. A number of lawmakers led by Sen. Jeff Sessions, R-Ala., have also been working to defeat it. Some talk radio hosts, including Mark Levin and Rush Limbaugh, have begun to voice deep unease despite the efforts of the bill's conservative standard bearer, Sen. Marco Rubio, R-Fla., to sell the legislation to them and other conservative opinion leaders. Talk radio was instrumental to the bill's defeat in 2007.