LAST August, when the Carter Administration sent Congress a package of proposals concerning “undocumented aliens,” more commonly called “illegals,” it was evident that a funny thing had happened on the way to the Capitol. For more than a year, public clamor had been increasing for the deportation of illegals and a tight seal of our borders. Yet the main thrust of the Administration’s package, though involving some restraints on new inflows, was to legitimize the presence and employment of most of the illegals already here and to assure their civil rights.