Here are the relevant items I found (a lot more at second link to read over)
In respect for their devotion to America, the Congress, by a joint resolution approved on May 11, 1950, as amended (64 Stat. 158), has requested the President to issue a proclamation calling on the people of the United States to observe each Memorial Day as a day of prayer for permanent peace
and designating a period on that day when the people of the United States might unite in prayer. The Congress, by Public Law 106-579, has also designated the minute beginning at 3:00 p.m. local time on that day as a time for all Americans to observe the National Moment of Remembrance.
http://www.whitehouse.gov/news/releases/2007/05/20070515-7.html“(6)
in Presidential Proclamation No. 7315 of May 26, 2000 (65 Fed. Reg. 34907), the President proclaimed Memorial Day, May 29, 2000, as a day of prayer for permanent peace, and designated 3:00 p.m. local time on that day as the time to join in prayer and to observe the National Moment of Remembrance; and
“(7) a National Moment of Remembrance and other commemorative events are needed to reclaim Memorial Day as the sacred and noble event that that day is intended to be.
http://www4.law.cornell.edu/uscode/html/uscode36/usc_sec_36_00000116----000-notes.html(3) calling on the people of the United States to unite in
prayer at that time; and
(4)
calling on the media to join in observing Memorial Day and
the period of prayer. Sec. 119. National Day of Prayer
-STATUTE-
The President shall issue each year a proclamation designating
the first Thursday in May as a National Day of Prayer on which the
people of the United States may turn to God in prayer and
meditation at churches, in groups, and as individuals.
http://uscode.house.gov/download/pls/36C1.txtI say we need a joint resolution to pray that bush gets impeached so that we may have that 'permanent peace'.