Obama's day: Immigration speech

President Obama devotes Thursday to his long-awaited executive orders on immigration.

In an 8 p.m. speech, Obama will discuss plans that would defer deportations for up to 5 million people who are in the United States illegally, an announcement that will touch off a fierce political battle with Republicans.

In announcing the speech Wednesday on Facebook, Obama said: "What I'm going to be laying out is the things that I can do, with my lawful authority as president, to make the (immigration) system work better -- even as I continue to work with Congress and encourage them to get a bipartisan, comprehensive bill that can solve the entire problem."

As Obama's aides brief lawmakers and supporters throughout the day Thursday, Republicans plan to argue that Obama's actions are illegal and an abuse of presidential power.

Some Republicans have pointed out that, in recent years, Obama himself has questioned whether he has the legal authority to defer deportations. They said his executive orders are more about politics and the Hispanic vote.

Obama said he must act because House Republicans have refused to take up a comprehensive immigration bill.

The immigration speech isn't the only item on Obama's schedule Thursday.

The president will also honor 19 new recipients of the National Medal of Science and National Medal of Technology and Innovation -- "our nation's highest honors for achievement and leadership in advancing the fields of science and technology," says the White House schedule.