Public Is Trending Toward Electing A Democrat As President

This chart was made from results of two Rand Presidential Election Panel Surveys -- the first taken in January, and the second done in March of this year. Note that in January the Democrats had a 3.6 point advantage (46.7% to 43.1%). By March, that advantage had grown to 15.1 points (53.0% to 37.9%). Clearly, the trend is toward growing support for a Democratic president and decreasing support for a Republican president.

I also found the chart below interesting (also from the Rand survey). It shows the perception of each candidates ideology by the public (with 1 being very liberal, 3 being moderate, and 5 being very conservative).

The chart helps explain why Democrats are preferring Hillary Clinton over Bernie Sanders. Democrats, on average, rate themselves as a 2.5 (moderately liberal), and that is also how they see Hillary Clinton. They see Bernie as a 2.0 (more liberal than they are).

It can also help explain why Republicans are choosing Trump over Cruz. Republicans rate themselves on average as 3.7 (moderately conservative), while Trump is rated as a 3.2 and Cruz is rated as a 4.3. They have opted for the one more perceived as moderate rather than the one viewed more extreme than they see themselves.

This is fairly normal for voters in both parties (and for Independents). American voters have always tended to prefer a more moderate candidate.