A.M. Links: Sidney Blumenthal Subpoenaed, David Letterman Retires, Senate to Vote on USA Freedom Act

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  Credit: White House / Flickr.com

  Congressional investigators have subpoenaed Hillary Clinton adviser Sidney Blumenthal, insisting that he testify next month before the House committee investigating the 2012 Benghazi attack.

• The Senate will vote this week on the USA Freedom Act.

• Islamic State fighters have gained partial control of the ancient city of Palmyra in Syria.

• "North Korea said Wednesday that it has the ability to miniaturize nuclear weapons, a key step toward building nuclear missiles."

• Inside the Texas biker gang wars.

• Late Show host David Letterman is retiring tonight.

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