The president, working against the ruling by a judge in WI, has details decided to go ahead and proclaim a national day of prayer.
In a proclamation from the White House, the president stated that in the past, when the going got tough, Americans prayed. Just because people hit their knees to pray when things got bad doesn't mean you have to proclaim a national day in which to chant at the sky. Here are some other things Americans do that don't get a proclamation: when we get horny, we have sex; when we get mad, we fight; when we get hungry, we eat. Who cares?
Just because Americans do something stupid when events go south doesn't mean you celebrate it. The wall between church and state is beginning to look a lot like wall between the US and Mexico: just move 20 miles away where the fence has a giant hole in it.