A 13% margin translates as 56%-43%. A 25% margin translates to 62%-37%.
The greatest percentage margins in the last century in binary races between winners and losers in the Presidential election have been roughly 24% (FDR vs. Landon), 23% (Nixon vs. McGovern) and 22% (LBJ vs. Goldwater). All involved an incumbent against a sacrificial lamb.
In case you wonder about 1984 -- the margin was 'only' about 18%... and Ronald Reagan won 49 states because partisan polarization between the states was practically nil.
Assuming that Hillary Clinton will be the Democratic nominee, she will imply some unique qualities in the campaign. Least important will be that she will be the first female nominee of one of the two major political parties for President. She will be the spouse of a former President, and as such she will know her way around the political process as few Americans have ever had. She has experience both in elected office and in the Cabinet.
We shall soon see whether the Republican Party will be an asset or a liability in 2016. Its politicians get to dominate the political discourse for two years, and by November 2016 we will see whether the political scene is more like 2010 -- or 2006.
In 1999, Bush was up 31 points on Gore. In 2003, Bush was up 28 points on Kerry.
