Sen. Tom Cotton on the sacred role of Arlington's Old Guard

Arlington National Cemetery is well known as the final resting place for fallen U.S. soldiers. Less famous is the elite unit that performs the funerals for these military heroes: The Old Guard, the Army’s oldest active duty regiment. Sen. Tom Cotton, R-Ark., who served in Afghanistan and Iraq as well as The Old Guard, covers it in his new book, “Sacred Duty,” and joins Judy Woodruff to discuss.