Whoa:

The comprehensive immigration overhaul being taken up in the Senate this week could cost taxpayers $6.3 trillion if 11 million illegal immigrants are granted legal status, according to a long-awaited estimate by the conservative Heritage Foundation.

The cost would arise from illegal immigrants tapping into the government’s vast network of benefits and services, many of which are currently unavailable to them. This includes everything from standard benefits like Social Security and Medicare to dozens of welfare programs ranging from housing assistance to food stamps.

The report was obtained in advance by Fox News.

“No matter how you slice it, amnesty will add a tremendous amount of pressure on America’s already strained public purse,” Robert Rector, the Heritage scholar who prepared the report, said in a statement.

Our immigration system is broken. There can be no doubt that it’s in serious need of reform.

But this reform? Even if you support it in theory, the fact is we just don’t have the money.

UPDATE: You can get Heritage’s full report in PDF here.