More evidence of our great American divide arrived last Friday in the form of some focus group studies undertaken by Stan Greenberg (Bill Clinton's pollster in 1992) and James Carville. They oversaw conversations with a group of hard-shell conservatives in Georgia. The fascinating results explain a lot about my country's political tensions and shed light on the question of what makes contemporary American conservatism – well, unique, let's call it.

They found that conservatives "stand a world apart from the rest of America" in terms of how they view Barack Obama and how they see politics. There is a continuum, in other words, in US politics, running from those on the left who've already concluded that Obama is a sellout, to mainstream liberals who are basically happy with him, to moderates who are approving but with reservations, to centre-right folks who are unconvinced but pulling for him to succeed, for the country's sake if nothing else.

Then there are committed conservatives. They're off the continuum, in three basic ways. First, they fundamentally question his legitimacy as president. Second, they believe that a successful Obama presidency would destroy the country and are "committed to seeing the president fail". And third, they think he is "ruthlessly advancing a 'secret agenda' to bankrupt the US and dramatically expand government control to an extent nothing short of socialism".

Big deal, conservatives will say to liberals. You people loathed George Bush. What's the difference? It's a fair question. But I think there is a difference. It doesn't repose in the character of either set of partisans – that is, I'm not saying liberals are better or fairer-minded than conservatives are. Rather, the difference has to do, I think, with the different ways liberals and conservatives define their relationship to their country.

On the first point, liberals questioned Bush's legitimacy, too. There is little doubt of that. Of course, there were solid empirical bases on which to do so. His campaign stopped the vote recount in Florida, and the supreme court, not the voters, put him in the White House. Around Obama's victory there were no such vexations. And the questions that do exist about Obama's legitimacy – his citizenship and religious affiliation – are fantastical fabrications. Be that as it may, let's be generous and acknowledge simply that legitimacy issues have been raised on both sides.

It is also true many on the liberal-left wanted to see Bush fail. We wanted him to fail at a lot of things. To some degree that's just politics. Matters get trickier when one discusses Bush's wars, because that raises questions about whether wanting to see him fail crossed the line into wanting to see America lose a war, however illegitimate that war might have been in liberal eyes. Most Bush opponents tried not to cross that line, but I can't say it was never crossed. So let's be gracious and call this one a wash too.

The third point is where the difference enters the picture. As much as liberals despised Bush, people never thought (except maybe on the fringes) that he was secretly out to destroy the US. We felt some of his administration's principles weren't American as we understood the concept (the arrogation of executive power, or the approval of torture). But there was none of this Manchurian Candidate business. Liberals assumed that Bush was doing what he, his team and their supporters believed was the right thing based on their understanding of American values and needs.

Conservatives do not believe this about Obama. Clearly some of this has to do with his background. Greenberg and Carville stress that race was not a factor in their all-white Georgia focus group, and while I would agree that conservatives' problems with Obama are far more ideological than racial, I have to believe that race is a subliminal factor of some sort. But it also has a lot to do with history.

One often hears conservatives speak of how Obama is destroying "my country". They use the "my" because conservatives tend to feel a type of ownership regarding the country that liberals don't. They are certain that they represent "real" American values, and that liberals represent alien values.

There's a long history here, which is bound up in everything from the two sides' different definitions of patriotism – "my country right or wrong" versus "I want to improve my country because I love it" – to religion to militarism to cosmopolitanism to a thousand other things. Every American presidential campaign, on some level, is about the Republican trying to frighten people into believing that the Democrat doesn't share "your values" and the Democrat trying to reassure people that he does. So, for conservatives, Obama is not just a guy whose views they vehemently disagree with. He's an ideological Typhoid Mary, a carrier of unknowable and barely comprehensible infections.

That is qualitatively different from liberal hatred of Bush. It is also, to be blunt, paranoid – because it's rooted in metaphorical narrative far more than in fact. And that means facts can never win an argument. Obama could leave office in January 2017 with the capitalist economy roaring and American power and security enhanced and these voters would still believe we'd escaped state ownership of everything and one-world government by a whisker. It's been part of the psychology of the American right for decades, and it sure won't be dissipating as long as Obama is in office.