So, from a brief spasm of curiosity, I tracked down what I think is the source and version of the quote about "wrapped in the flag and carrying a cross" that's usually attributed to Sinclair Lewis. (Hewey Long is also sometimes named.) The bad news is this version may today be even more depressing than the misattributed.
Poking Google Books with assorted keywords from the quote eventually turned up the February 5, 1936 issue of The Christian Century (Volume 53; page 245). It's only available in Snippet View that way, and alas the local university library doesn't have the issue (they're missing that volume in dead-tree, and the electronic versions only start with the 1946). No doubt someone will eventually drag it from their local library onto the Internet. However, though there's more to the article some persistent tapping at snippets meanwhile loosened what looks to be a sub-title and opening paragraph.
Speakers Draw Dark Picture of Future
James Waterman Wise, jr., in a recent address here before the liberal John Reed club said that Hearst and Coughlin are the two chief exponents of fascism in America. If fascism comes, he added, it will not be identified with any "shirt" movement, nor with an "insignia," but it will probably be "wrapped up in the American flag and heralded as a plea for liberty and preservation of the constitution."
OK, we have someone who's preaching to other liberals - actually, outright Marxist intellectuals. But William Randolph Hearst's yellow journalism has an apt multimedia student in Rupert Murdoch; and radio preacher Father Charles Coughlin has apt students in Rush Limbaugh and Glenn Beck, neither of whom has an archbishop to answer to. (Yes, even before the Archbishop's final "shut up" order some blatant radio and mail censorship had him almost silenced; if that's the alternative, I'm not sure that's any improvement.)
But what would the Tea Party ilk care about what some egg-head commies were told during the depression? After all, they've wrapped themselves up in the American flag to plead for liberty and preservation of the Constitution.