How Much Difference Does Clinton or Obama Make?

The Electoral College maps posted here on FHQ recently (this week and last week) have begun to provide a glimpse into how both Clinton and Obama would do against John McCain in November, but represent only a partial picture of the possible candidate effects at play in a potential general election. Aggregating through the electoral college indicates overall who would win a state or the general election, but does not provide a true sense of how big a given candidate's impact is in any particular state.

To get a better idea, then, of how much an effect Obama or Clinton has in a state we can take the difference between both their margins against McCain. Very generally, the larger the difference, the bigger the impact one of the candidates has. For example, Obama has a 30 point advantage over McCain in Hawaii but Clinton's edge is only four points. Obama's 26 point differential (henceforth, the McCain margin) there means that his impact is the difference between Hawaii being solidly Democratic or it being a toss up.

There are some caveats though. The differential may be huge but not make much of a difference. In Utah for instance, Obama has a decided edge in the McCain margin against Clinton but the difference is between being blown out and really being blown out. The size of the margin then, doesn't matter unless the advantaged candidate is either competitive with McCain or beats the Arizona senator while the other Democrat loses to him. The other issue is that if the state is already a toss up, it requires less of an advantage to make a difference. So Clinton has modest McCain margins against Obama in the traditional swing states from the last few cycles (PA, OH, etc.). As small as that differential is, it could be a deciding factor in which party wins those states.

What can we derive from this measure? First off, it indicates that Obama does better in 34 states. He flips a state to the Democratic column in 10 of those cases (CO, IA, MI, MN, NV, NH, NM, OR, WA and WI) with his McCain margin in each ranging from 5-25 points. Five other states are competitive when Obama is against McCain and Clinton is not (NE, SC, SD, TX and VA). The remaining states are either solidly Democratic or solidly Republican.
*Note: States in white are states where the Clinton has a greater McCain margin.
***CORRECTION: Wisconsin should be in the 10-14.99 (dark green) category.

In Clinton's case, she has advantages in 15 states (Yes, that's just 49 states total. Alaska and the District of Columbia have been omitted since no data is available. In the electoral college maps, Alaska was rated a Strong McCain state while DC was a Strong Democratic state.). For her part, Clinton is able to turn both Arkansas and West Virginia blue, is more comfortably ahead of McCain in Massachusetts and New Jersey, and holds a slight (and potentially significant) McCain margin over Obama in swing states like Pennsylvania and Ohio. She is also more competitive in Missouri and Florida.
*Note: States in white are states where Obama has a greater McCain margin.

Side by side with the electoral college maps, these maps expand the understanding of who is doing well in which states, and beyond that, how much impact either Obama or Clinton has over the other versus McCain.

Updates for these maps (4/9/08)

[Thanks to Bill Chittick for the suggestion on the map idea.]