President Barack Obama has signed into law a major education law setting U.S. public schools on a new course of accountability.

Obama signed the bipartisan rewrite of No Child Left Behind at the White House on Thursday.

The law will change the way teachers are evaluated and how the poorest performing schools are pushed to improve.

Obama calls the law a "Christmas miracle." He's praising Republicans and Democrats for coming together to pass the long-awaited legislation.

Obama says the Bush-era No Child Left Behind law had the right goals. But he says in practice it fell short and used a cookie-cutter approach.

The new law turns more decision-making powers back to the states.