WASHINGTON (Reuters) - Attorney General Eric Holder on Wednesday sought to distance himself and other senior Justice Department officials from a botched operation to track guns smuggled to Mexican drug cartels, saying they were not involved. The Obama administration has been under scrutiny after revelations that as many as 2,000 guns were sold to suspected gun traffickers, not properly tracked and ended up at crime scenes in the United States and Mexico. The operation, dubbed "Fast and Furious", was run by the Bureau of Alcohol, Tobacco, Firearms and Explosives and the U.S. Attorney's office in Arizona. Congressional Republicans have questioned...