We shouldn't use the word Fascism lightly. The US certainly isn't fascist today but the crisis has opened the door to political uncertainty. We can't see where things could go and that's worrying enough. That being said Fascism, as it was in the 20th Century, is not simply going to spring up again. It will come in a very different form, don't forget Fascism doesn't really have any universal or coherent set of characteristics (except maybe an extreme reactive tendency of nationalism). The similarities between America and Germany in the 20s are quite worrying because we know what happened in the Wiemar Republic. This isn't unique to America at this time, a poll found that 48% of Brits would vote for a far-right party if it wasn't fascistic in imagery. It's not unusual to see a rise of anti-immigrant nativism and nationalist populism in recessions, but this isn't just another recession. Walter Benjamin seems to have it right when he deemed Fascism to be the product of a failed revolution.
The United States is effectively the only society on earth founded as a federal capitalist republic. There is no monarchical feudal backdrop as there is in Europe and this means that American conservatism tends to be quite different from traditional conservatism in Europe. It's not that the Europeans don't have a long history of extermination, slavery and war (if anything Europe has a longer history) but the Americans have a 'blanking out' point in a much clearer way. You can pin-point the 'beginning' as it were, which is the basis of the American national mythology. This will become a basis of an ideologico-spiritual crisis with American decline, as it was for the British who have yet to fully accept what happened in 1945. There are upsides in American ideology that Europe lacks. Don't forget that Jefferson wanted a revolution every 20 years including a reassessment/revision of the constitution. The idea is of a permanent renovation of 1776.
If we're going to carry out a strict comparison of the US and the Fascist states of the 1930s then there are problems with the analogy. For one thing American nationalism tends not to sever itself from the values of the Enlightenment, it at least has to maintain the pretence of standing for and defending those values. Fascism was always about the destruction of the whole Enlightenment project of rights and freedoms. This is what separates Stalinism from Fascism, can you imagine the Nazis putting Jews on trial before the Holocaust? This is the reason that there were show elections held in Tito's Yugoslavia and Stalinist Russia was officially a 'people's democracy'. Even the erosion of individual rights and liberties in the US has yet to sever the cord to the Enlightenment totally. In fact it's often the case that this encroachment on the individual is accomplished within the same framework, under the umbrella of 'security' and so on.
The promise of an alternate modernity devoid of class struggle is completely missing for one thing. You have to keep in mind that the Fascists promised a 'Third Position' beyond socialism and capitalism. There is no racialised populism rooted in notions of 'blood and soil' that displaces the class struggle into a fight to preserve an organic society from a Jewish-Masonic-Bolshevik cabal. There is definitely scapegoating, racism and red-baiting, but it's not on the same scale at all. The racial myths that the Nazis adhered to came out of England originally and were predominant in the US for a long time. Now it's only the KKK and other fringe lunatics that adhere to the myth of a master race. As for militarism and civil authoritarianism, these things are not unique to Fascism but are not new to America either. The US has possibly killed in excess of 10 million people since the end of WW2, Nazi Germany set out to exterminate about 40 to 50 million Europeans and set off a chain of events that left 60 million dead.
I'm not sure that there is a word which neatly sums up the US situation. It is a business run society devoid of any safety net with an authoritarian state and bloated military. It's clear that really existing democracy is decaying in front of our eyes, but it seems unlikely that there will be a dictatorship in America tomorrow. It's not always easy to sum up an entire political system with one word, luckily Hitler and Mussolini named their system - while in the US there is officially no ideology and no system. The widespread attitude is a suspicion of politicians, parties and the government rather than a worship of any of these things. Even the radical Right in the US seems to be in the grips of an anti-political purism, the theoconservatives and neoconservatives have been marginalised by a libertarian push that the GOP are trying to use to destroy what's left of government programmes. I'm not saying that there aren't things that we should be worried about and that there could never be an American fascism. But let's try not to use the word loosely.