100 Million and Counting?

The Heritage Foundation released a study that should give every American pause. Here's the first paragraph:

If enacted, the Comprehensive Immigration Reform Act (CIRA, S.2611) would be the most dramatic change in immigration law in 80 years, allowing an estimated 103 million persons to legally immigrate to the U.S. over the next 20 years—fully one-third of the current population of the United States.