The Legal Battle Over Obama's Immigration Plan

President Barack Obama's plan to take the immigration system in his own hands is a daring test of the limits of presidential power.

The steps he will lay out tonight in a prime time address will fuel a debate over his use of executive authority to enact change without the agreement of an opposition Congress.

Conservatives are howling that Obama's effort to shield millions of illegal immigrants from deportation oversteps his own authority and infringes the Constitution. His backers say he's simply exercising his power to select which areas of law to prioritize - and addressing a major national issue that seems to elude Congress.

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