@Leonard,
I think it's been pretty well documented that Americans tend to be less informed about their world than people in many other lands.
I think the fault lies in the horrible decline in the American media which, as previously noted, has lapsed from an information vehicle to more of an entertainment-directed voice ("if it bleeds, it leads"). This is by no means unique to the United States but you have spawned the likes of Beck and Hannity and O'Reilly. I think the level and scope of misinformation is higher in the United States than elsewhere in the West.
I recall one study that found something in the order of 60% of FOX viewers were convinced that WMDs had been found in Iraq two years after the Bush administration acknowledged no such weapons existed. Those are people who have been duped by their media of choice.
Are Americans more divided at the moment? I think so. I don't recall having seen your countrymen this divided since the final years of America's war in Vietnam. I think Americans became more cohesive after that, their unity peaking under the Reagan administration. For all his many flaws, Ronald Reagan made the American people truly proud to be American again.
Now Leonard you contend that liberals "mouth off" that government is terrible but who was it who uttered the mantra that "government isn't the answer, it's the problem"? I don't think Grover Norquist or any of the legions of neo-cons were liberal either, do you?
Can Americans again find bipartisan unity? I think it's definitely possible but it will take a genuine restoration of America's middle class. The middle class is less tolerant of partisanship, left or right, and sees a vested interest in social cohesiveness. Whether the will to achieve that remains and whether that option will be overtaken by events shaping today's world is unclear. There was an awesome vitality and robustness, a genuine sense of confidence that bolstered America while the middle class flourished.
Finally, do I see these problems in my country, Canada? To some extent, yes. The evidence is most plain in those provinces that had American-style manufacturing economies. We too have seen a widening of the gap between rich and poor albeit not on the scale you have experienced. I suppose we weather these changes a bit better because, liberal or conservative, were a more cohesive society. Polls repeatedly show both sides tend to be socially moderate and to strongly support our social welfare programmes and public healthcare, for example.