Best example I can think of is Bill Clinton in 1993 vs "Republican challenger". We had that won until we picked Bob Dull. Same thing may happen again with the current Republican leadership.
Bob Dole was solidly behind in practically every poll going into the elections, before he lost to Bill Clinton.
You example doesn't hold any water.
I asked for an example, where the GOP candidate was solidly ahead in the polls going into the elections, and ACORN, SEIU etc managed to steal the elections for the Democrats, like that poster “Drill Thrawl” was talking about in his post # 75 here:
http://www.freerepublic.com/focus/news/2412931/posts?page=75#75