WASHINGTON - Immigration overhaul will stand as the most glaring failure in President Barack Obama's 7 ½-year effort to enact his vision of social change.

Despite two campaigns full of promises and multiple strategies, Obama imposed only incremental, largely temporary changes on the immigration system. He leaves behind a system still outdated and with some 11 million people living in the U.S. illegally.

Obama's legacy will be judged by a sometimes contradictory mix of policies. He protected roughly 730,000 young people, a generation of so-called Dreamers, who were brought to the U.S. illegally as children.

His administration also aggressively enforced immigration laws - deporting more than 2.4 million people.