Just as reference: At this stage in 2012, Obama/Romney a cliff-hanger. In Nov, Obama won by 5 million votes, 4% margin, 332-206 EV.
At this stage in 1992, Ross Perot was runway leader over Bill Clinton and GHW Bush. See NYT story June 11 1992 below.
At this stage in 2004, Kerry in lead over GWB