It appears he was invited in his capacity as (my emphasis)

Tebow was seated on the platform along with the following:

The President of the United States, Barack Obama
The Vice President of the United States, Joe Biden
Chairman of the Joint Chiefs of Staff, Admiral Mike Mullen
The Prime Minister of Spain and Chairman of the European Union, Jose Luis Rodriguez Zapatero
Senator Orrin Hatch
and the Key Note Speaker, Hillary Clinton, Secretary of State

3000+ were in attendance and the breakfast was Co-Chaired by Sen. Amy Klobuchar of Minnesota and Sen. Johnny Isakson of Georgia.

Now this is interesting. The EU organizes a yearly EU/US summit and Obama says he's not interested in attending. Yet the US thinks nothing of inviting the rotating President of the European Council to a random US domestic event and he accepts. What conclusion should we draw from this?

En un viejo país ineficiente, algo así como España entre dos guerras civiles, poseer una casa y poca hacienda y memoria ninguna. -- Gil de Biedma