WASHINGTON (AP) — Senate Democrats have blocked a Republican effort to prevent President Barack Obama from acting unilaterally on immigration. Sens. Jeff Sessions of Alabama and Ted Cruz of Texas pushed a measure that would have prevented Obama from taking executive action to curb deportations for immigrants in this country illegally. The White House says Obama intends to take such action by the end of the year, possibly protecting millions from deportation. Republicans say that amounts to "executive amnesty." The measure also would have shut down an existing Obama program that provided work authorizations to certain immigrants brought here illegally as youths.