States vs Feds on illegal immigration

What's the difference between the states and the feds when approaching illegal immigration?
The key difference seems to be that the states go after everybody, everywhere, whereas the federal approach focuses on law-breakers.

Not only have state officials in Oklahoma, Utah, Indiana, and Arizona, among others, begun to deport illegal immigrants in the U.S., but statistics released today show the federal Immigration and Customs Enforcement (ICE) has deported—get this—almost three times as many people as they did the preceding year. 64,000 from September 2005-September 2006 to what is now 164,000 from September 2006-2007. Money Quote:

"It used to be two parties in the courtroom: the state and the defense," said Marian C. Cordier, a Rockville defense lawyer. "Now you know immigration is waiting in the wings."