With the U.S. financial crisis hanging in the balance, the first debate between Barack Obama and John McCain – originally scheduled for Friday — has taken on unusual importance.  But, how will this first presidential duel of the 2008 election compare with the most-watched debates of the last half-century?
Jimmy Carter and Ronald Reagan’s October 28, 1980 debate claimed the largest television audience — 80.6 million viewers — since 1976, the first year that Nielsen collected TV viewership data for presidential debates. 
George H. W. Bush, Bill Clinton, and Ross Perot’s October 15, 1992 debate (69.9 …