By Roberta Rampton and Ayesha Rascoe WASHINGTON (Reuters) – President Barack Obama will review briefing documents from his staff this weekend on potential Supreme Court nominees, the White House said on Friday, as a tough political fight loomed with Senate Republicans over filling the pivotal vacancy. The White House arranged for photographers to snap pictures of Obama carrying a thick binder filled with papers during his walk from the Oval Office to his residence on Friday night as he ponders who to pick to replace conservative Justice Antonin Scalia, who died on Feb. 13. Earlier in the day, the president and first lady Michelle Obama paid respects to Scalia as the late justice's body lay in repose in the Supreme Court's Great Hall.