bipartisan immigration bill soon to be introduced in the Senate could exclude hundreds of thousands of immigrants here illegally from ever becoming U.S. citizens, according to a Senate aide with knowledge of the proposals.

The bill would bar anyone who arrived in the U.S. after Dec. 31, 2011, from applying for legal status and ultimately citizenship, according to the aide, who was not authorized to discuss the proposals before they were made public and spoke on condition of anonymity.

It also would require applicants to document that they were in the country before Dec. 31, 2011, have a clean criminal record and show enough employment or financial stability that they're likely to stay off welfare