In a piece a week ago, we argued that for all the talk of President Obama's dipping poll numbers the truth of the matter was that his approval (and disapproval) marks have varied very little since he took office.

But, we wondered, how did the relatively small movements in Obama's approval ratings compare to other past presidents? Now, thanks to the good people at Hamilton Place Strategies, a GOP economic consulting firm, we have the answer.

In the chart below, you see each term of the five presidents who have held the office since 1980 rated by the standard deviation in their approval ratings. Standard deviation essentially means how clustered a certain set of data is; the lower the standard deviation, the more clustered. (Here's a fuller explanation of standard deviation for you nerds out there.)

President Obama's standard deviation for his first term was 6.3, the third lowest of the post-1980s presidents.  Interestingly, the only president with a lower standard deviation in his approval ratings is President Bill Clinton who had a 3.7 deviation in his second term and a 5.5 deviation in his first.

That data proves illustrative of our broader point that partisanship has grown so acute in the past 15 (or so years) that there's little that can really make the numbers fluctuate.

The exception to that, according to the numbers above, is the outbreak of war. Both George H.W. Bush and George W. Bush carried high standard deviations in their first terms (for H.W. Bush it was his only term) due to war. When the U.S. initially went to war, the presidents' approval ratings soared but they faded from those heights as their terms wore on.