White House Picnics began after end of World War II
The tradition dates back to September 1945, when President Harry Truman hosted 150 Democratic Members of Congress at the Jefferson Islands Club in the Chesapeake Bay, per the White House Historical Association.
In 1967, President Johnson and his wife, Lady Bird, hosted a "Country Fair" celebration on the South Lawn for children and grandchildren of members of Congress, Cabinet members and other government officials. Since then, the picnic has provided a casual atmosphere for socialization and camaraderie between the President and both sides of the aisle.
"Rosalynn Carter, looking slightly over dressed in a navy skirt, white vest and sensible shoes, said she would have worn her blue jeans, but left them in at home Plains, Georgia. 'I left all my comfortable clothes at home,' she said with a hint of resignation," a Washington Post report from the 1977 picnic reads.
The Reagans, both Bushes, Clintons, Obamas and Trumps all hosted their own picnics over the years, with themes ranging from "Taste of the States" to "Hawaiian Luau." Picnic performers have included Tammy Wynette in 1982 and the band Alabama in 1991.
But the evening has also fostered a more relaxed environment open to some entertainment from the administration: George W. Bush press secretary Tony Snow played the flute with his band in 2007, his chief of staff Joshua Bolton played the bass in 2006, and Obama press secretary Robert Gibbs hit the dunk tank in 2009.
The Trumps first picnic in 2017 included a face painting station, a carousel, sailboat racing in the South Lawn fountain, and entertainment from the United States Marine orchestra, which played a combination of showtunes and patriotic numbers. There were also snack stands set up with popcorn, cotton candy and soft pretzels, as well as a full menu of traditional picnic fare. Strings of lights were hung over green and yellow-clothed tables.