On the hottest flash point in the debate, Arizona's new law targeting illegal immigrants, Mr. Obama said the rules are "unenforceable" for local police. But he didn't give any indication when the administration will file an expected lawsuit seeking to block the new law, which takes effect at the end of this month.

Mr. Obama has already missed his own self-imposed deadline for getting a broad immigration bill passed. During the 2008 presidential campaign he told Hispanic audiences he wanted a bill in his first year.

And his new push is unlikely to bear fruit this year.
Obama tries to put Republicans on immigration hot seat - Washington Times

We'll find out shortly how "unenforceable" the AZ law is soon.