While Cheney's role at the convention was officially in flux Tuesday, CNN said its source confirmed that there was a "mutual understanding" between Cheney and presumptive nominee Sen. John McCain's camp that made the vice president's presence at next month's convention unlikely.

While Cheney remains popular with conservatives, McCain, R-Ariz., has been distancing himself from the Bush administration in his close race with Sen. Barack Obama, D-Ill..

The convention is set for Sept. 1-4 in St. Paul, Minn.