Nixon might have actually known that he was smuggling pot for Louis Armstrong. Since Customs agents had been informed that contraband was being imported into, New York all customers including Armstrong who was returning from his tours as a 'Goodwill Ambassador' was lined up for inspections. Since he was actually carrying three pounds of marijuana in his suitcase, he was to be interrogated but Nixon's timely entry into the scene saved him. The whole incident actually leaves room for doubt as to whether Nixon actually knew he was smuggling pot for Louis Armstrong.
After returning from an international tour, Louis Armstrong was waiting to go through customs at the Idlewild Airport in New York. Vice President Richard Nixon was also there after travels, and he took the opportunity to approach the famous musician and spare him the trouble of going through customs. Nixon chivalrously took Armstrong's luggage, and unknowingly, a large amount of pot, through the US Customs. After the event, Nixon's traveling aid heard from other jazz musicians of what had happened. He told Nixon, who was genuinely surprised that Armstrong even smoked marijuana. Of course Nixon didn't know he had smuggled pot through customs, if the Vice President sees a celebrity they admire, of course he will offer to take their luggage for them.
Louis Armstrong was returning to the United States from a trip abroad as a good will ambassador. He landed in New York and was sent over to the customs line. Nixon knew that Armstrong was arriving and was hoping to have a picture taken with Louis Armstrong. Nixon greeted Armstrong upon entering the custom's lounge. Then, Nixon asked Armstrong if there was anything Nixon could do to help, Armstrong reportedly asked told Nixon that he was tired and had been told to wait in the custom's line. Nixon grabbed Armstrong's bags and marched him past customs. It so happened that Armstrong's trumpet case contained three pounds of marijuana. Nixon never had a clue and later when informed about it, expressed surprise that Armstrong smoked pot.
While I believe that Richard Nixon did indeed smuggle pot for Louis Armstrong, he did not knowingly do so. He was a victim of social engineering from the music star, whom he had previously befriended and did not think twice to perform a favor to assist somebody about which he felt kindly.