"radical groups in American politics, such as the Tea Party conservatives."
"The Tea Party" can only be counted as radical if fiscal probity and a less intrusive Federal Government are radical ideas. Calling them radical means that Obama was mouthing radical slogans, at least as to fiscal probity, during his 2008 campaign.
Second, there is not now nor was there ever a unified "Tea Party" movement with an organization, a platform, or an ideology. At best there was memetic symbolism derived from American History that expressed the deep unhappiness of a lot of Americans in 2009 -- 2010 with the way that the Obama Administration was governing the country, in particular with the size of the deficit and Obamacare.
This discontent was so extreme and radical that the President's party lost control of Congress in the 2010 election.
"longing for an imagined whitebread small-town America of the past."
As George Will said: "Professors have reasons for their beliefs. Other people, particularly conservatives, have social and psychological explanations for their beliefs."
Outside of the fact that no one has even polled, let alone psychoanalyzed conservatives opposed to the administration and their congressional allies in both parties, it is, at best condescending, to attribute expressed policy beliefs to the inner mental states of people you don't know and have never meet. I could also call it insulting.
I do not think it requires any amateur Frankfurt School theorizing to oppose tax increases of the size and scope enacted in 2009-2010. The increases at the end of 2012 were just icing on the cake. Here I rely on the often cited insight of Milton Friedman that deficit spending is a commitment to future tax increases. Not only that, but the Federal Reserves cramdown of interest rates is an additional levy on savings.
I should also point out that the whole idea that blaming conservative resistance to the Obama Administration is based on nostalgia carries a heavy dose of irony. The real party of nostalgia has been the Democrats whose expressed desire is to restore a union dominated manufacturing sector in a world that has moved on. Remember the GM and Chrysler Bailouts. Iconic Democrat theorist Paul Krugman wrote a book about restoring the conditions that prevailed in the 1950s when he was a child. Time Magazine ran a cover showing Obama posed as FDR.