Somebody help me out with this.
My reading of this whole "spread the wealth" thing is that, while Obama's use of the phrase may have been essentially a slip of the tongue, Obama's support for progressive taxation, and Joe the Plumber's criticism of it, are why we've arrived at a discussion about socialism, and the government coming and taking your money away. (If you're in the top 5% of the country, that is. To those who are suggesting that making $250,000 actually makes you middle class-- the term "middle class" has the word middle in it. It means you're in about the middle of our country, in terms of wealth or income. If you make more than five times the median income-- that is, the middle income-- you can't be middle class.)
Well, I think we could have an election that involves a major debate about the progressive income tax, but in order to have it, we'd have to have a candidate who is actually opposed to progressive taxation. The alternative to progressive taxation is a flat tax, and John McCain is not a flat tax supporter. If this "spread the wealth around" argument is an argument with actual substance, instead of pure political opportunism, it has to be waged by people who are actually opposed to progressive taxation, in favor of a flat tax. John McCain, as much as he may want to limit the slope of the tax line, isn't in favor of a flat tax; it's not in his policy proposals at all. Could you have a simple "let's have a more regressive tax scheme than we currently do" argument? Sure. But that can't be this scorched-earth, progressive taxation equals socialism argument the McCain campaign is making. It just doesn't make sense to have this extremist argument when the candidate making it isn't on one of the extremes.
Additionally, conservative history-- or at least, Republican history-- simply isn't filled with flat-tax supporters. Steve Forbes famously ran on a flat tax. (And performed famously poorly.) But we've had the progressive income tax since Teddy Roosevelt, a Republican and John McCain's hero. George W. Bush has never agitated towards a flat tax, as far as I can see. Neither did Bob Dole. Neither did George H.W. Bush. Neither did Ronald Reagan. They all to one degree or another advocated alleviating the tax burden on the wealthy, but they didn't propose a flat tax in any kind of serious way. That's a consequence of the fact that Americans of both ideologies just very broadly support progressive taxation, find it natural and fair, and aren't particularly animated to end it. It's not that the electorate hasn't heard this story about progressive taxation. I think it's that they just don't care.