Those tougher checks seem to have focused on immigrants from certain countries.

It is a major source of information on immigrants to America before 1750.

"The most immediate impact will be on legal immigrants," he said.

America, it seems, is more dependent than ever on immigrants for its scientific skills.

The rules, however, do not appear to shut the door on illegal immigrants.

The agents will concentrate instead on immigrants from other countries.

New York spends at least $800 million a year on illegal immigrants.

State officials say the move is not intended to crack down on illegal immigrants.

Most studies on immigrants have found higher rates of crime.

Like politicians who want to slam the door on immigrants.