WASHINGTON, Dec. 14 - For American intelligence agencies, the capture of Saddam Hussein is a much needed vindication after many months of failures and frustrations, Bush administration officials and members of Congress said Sunday. The agencies' standing was brought to a low ebb by a long line of setbacks, including the failure to anticipate the attacks on Sept. 11, 2001; the unsuccessful search for unconventional weapons in Iraq; and the inability to find Mr. Hussein or Osama bin Laden. But that string has ended in the dirt hole where Mr. Hussein was finally found, not far from his birthplace. Although...