Actually, there’s more to it than that: Americans don’t just think Barack Obama is a liberal; they also think he’s decidedly to the left of them, according to a new USA Today/Gallup poll. USA Today reports:

On a scale of 1 to 5 — with 1 being very liberal and 5 being very conservative — respondents rated themselves as a 3.3 ideologically, slightly to the right of center.

They perceive Obama to be a 2.3, to the left of center.

Some of the Republican candidates are more aligned with the respondents, said the poll: “Americans perceive Jon Huntsman, Mitt Romney, and Ron Paul as closest to themselves ideologically, and Michele Bachmann and Barack Obama as furthest away.”

I’m far less baffled by the majority’s opinion of Obama than I am by the 23 percent of respondents who describe the president’s views as “moderate” and the additional 15 percent who describe the president’s positions as “conservative.” Am I to understand that 38 percent of Americans either (a) have even more radical views than Obama, compared with which his seem “moderate” or “conservative” or (b) don’t understand the meaning of the terms “moderate” and “conservative”?

More relevantly, though, this could be a somewhat positive indicator of the president’s vulnerability as an incumbent (declining unemployment rate and brief positive blip in his approval rating notwithstanding!). As the poll summary puts it, “If Americans chose their president solely on the basis of the fit between their own ideological views and their perceptions of the candidates’ views, Huntsman, Romney and Paul would be in the best position for the 2012 election.” Then again, Americans don’t choose their president solely on ideological fit — and they’ve viewed Obama as a liberal pretty much from the minute he took the national stage.

For whatever reason, this poll makes me think Newton’s third law of motion is as applicable to politics as it is to physics. “For every action there is an equal and opposite reaction.” The American people seem to be reactionary voters at least as often as they are proactive voters — and, if they were more inclined to vote for a liberal in 2008, after eight years’ worth of what they perceived as relatively “conservative” policies, it seems probable to think they’ll be less inclined to vote for a liberal in 2012, after four years’ worth of transparently liberal deficit spending. Meantime, their views never really change. In other words, fear of extremes as much as any concretely held opinions seems to be voters’ most visible operating principle.