President Obama’s decision to issue a Proclamation for the National Day of Prayer but take a pass on the East Room festivities laid on by his predecessor seems pretty much of a piece with James Madison’s efforts to walk the line between custom and constitutional mandate in the matter of presidential religious leadership. As Madison put it in a letter written near the end of his life:

There has been another deviation from the strict principle in the
Executive Proclamations of fasts & festivals, so far, at least, as
they have spoken the language of injunction, or have lost sight of the
equality of all religious sects in the eye of the Constitution. Whilst
I was honored with the Executive Trust I found it necessary on more
than one occasion to follow the example of predecessors. But I was
always careful to make the Proclamations absolutely indiscriminate, and merely recommendatory;
or rather mere designations of a day, on which all who thought proper
might unite in consecrating it to religious purposes, according to
their own faith & forms. In this sense, I presume you reserve to
the Govt. a right to appoint particular days for religious worship
throughout the State, without any penal sanction enforcing the worship.

The Day of Prayer is one of those religious encrustations that have formed on the body politic since World War II. (Cf. “Under God” in the Pledge.) Established by Truman in 1952 and given a date regular (the first Thursday in May) by President Reagan in 1982, it’s become the province of a Task Force run out of Focus on the Family headquarters by Shirley Dobson, wife of James. She professes to be disappointed at the president’s decision but religious indiscriminacy is not, shall we say, Focus’ forte. We await the Proclamation.