Dr. Tichenor's testimony (here) is an informative survey of U.S. immigration history.
One point that the history makes clear is that even while nativists have always harassed immigrants, and they were periodically successful in imposing severe limitations on the country's insatiable appetite for immigrant labor, there has been--in policy and/or practice--exceptions for Mexican and Canadian workers.
In concluding his remarks, Dr. Tichenor issues this warning:
Our rich immigration history provides us with important lessons for contemporary immigration reform. First, we would do well to remember that the ideological traditions that have shaped our vibrant immigration debate since the nation's founding are driven by well-meaning and distinctive conceptions of the national interest. Second, our past reveals that each wave of "new" immigrants has been scorned by critics as incapable of successfully joining our ranks, only later to distinguish themselves among our most loyal and accomplished citizens. Finally, the origins and development of our illegal immigration dilemma highlights a series of compromises over time that fed the nation's appetite for cheap labor while creating a vulnerable shadow population and undermining the rule of law. The consequences of these compromises underscore why our generation must make tough choices to fix the system, recognizing the practical and ethical reasons for giving workplace enforcement real teeth and for giving undocumented immigrants an opportunity to earn legal status.It's interesting and important history. Click here for a PDF file of Dr. Tichenor's testimony.