This one fits a typical pattern we've seen over the years in which those on the left are the liars (yes, there are other patterns where the right is lying). The pattern is this:
Democrats push new proposal X
Republicans claim X will lead to Y
Democrats claim this is a lie and the proposal clearly prevents Y from happening.
After a passage of some period of time, Y is the norm and those who continue to oppose Y are [insert appropriate anti-reactionary epithet]
Where have we seen this before? The Civil Rights Act, for one. Opponents claimed that it would lead to quotas. Proponents pointed out the act specifically bars quotas. Before we knew what hit us we had the EEOC and affirmative action was ensconsed thoughout the land, prosecuting instances of "disparate impact." Opponents are accused of bigotry.
This of course has been definitively documented by Paul Craig Roberts.
YLE goes on to say
When the immigration reform act was passed in 1965, Ted Kennedy promised Americans it would not lead to a shift in the nation's ethnic balance. Well, a dramatic shift has indeed occurred. Imagine arguing on TV today that immigration is a problem because it has changed our ethnic make-up.
The "Ted Kennedy promised Americans" link goes to a comment site where So Much for Promises - Quotes Re 1965 Immigration Act has been posted (without links).
"immigration is a problem because it has changed our ethnic make up"