At least three White House officials had some knowledge of a controversial federal gun-running investigation that resulted in a large number of guns falling into the hands of Mexican drug cartels, according to emails the Justice Department sent to Congress. However, the emails do not indicate that the White House aides were briefed on the most controversial aspect of Operation Fast and Furious: the practice of allowing guns to “walk” or move across the border with little or no interference by law enforcement officials despite their suspicions that the guns were headed for drug gangs. The new emails, delivered to...