From NY Post:

WASHINGTON — President Obama turned down a chance to have Timothy Cardinal  Dolan deliver a prayer at the Democratic National Convention after Dolan told  Democrats he would be “grateful” to deliver a blessing in Charlotte.

Dolan — considered the top Catholic official in the nation, as head of the  Archdiocese of New York and president of the Conference of Catholic Bishops — tipped off Democrats a few weeks ago that he had agreed to deliver the  prime-time benediction at the Republican convention in Tampa next week, Dolan’s  spokesman Joseph Zwilling told The Post.