WASHINGTON (May 6, 2013)--The conservative Heritage Foundation says in a new report that the bipartisan immigration legislation pending in the U.S. Senate would cost taxpayers $6.3 trillion.
The study from the Republican-led group, which is opposed to an immigration overhaul, is sure to come under fire.
The libertarian-leaning Cato Institute called it "fatally flawed."
Critics say it doesn't measure economic boosts from the bill.
Heritage said the costs come from more than $9 trillion in government benefits to newly legalized immigrants over their lifetimes, only partially offset by $3 trillion they would pay in taxes.
During Congress' last immigration debate, in 2007, a Heritage report said the bill under consideration at the time would cost $2.6 trillion.
The conclusion was criticized, but carried weight with Republicans and the bill was defeated.