But that raises a more fundamental point: Both Vinik and Gerson cite Republican proposals to combine federal welfare spending into a single stream, give it to states to spend as they see fit, and claim that the resulting improvement justifies spending cuts. Once upon a time, this was Richard Nixon’s big new idea; block-granting everything to the states was also a centerpiece of Ronald Reagan’s domestic agenda. So, forget “new.” What constitutes an “idea”—is it a zippy new name (Senator Marco Rubio’s “Flex Fund”)? Is it the specific policy prescription, like block-granting? Or is it the underlying policy—in this case, finding clever ways to squeeze money out of programs for poorer Americans without overtly saying so, which has been Republican policy for 50 years?

The level of abstraction at which you define the meaning of “idea” determines whether anything is new under the sun. If you want to be specific enough, dressing up old ideas in new names or adding small new twists—most of what passes for policy these days, especially in campaigns—then everything is a “new idea.” From a broad perspective, however, nothing is: Virtually all proposals today are simply part of both parties’ long-running attempts to bring to fruition the agendas each has been pursuing, largely unaltered, for the last 80 years.

Both parties, like the two-dimensional characters of Flatland, are locked into a frame of reference—the 20th century welfare state—that is increasingly irrelevant. Scholar Phillip Bobbitt has argued, for instance, that “whereas the nation state justified itself as an instrument to serve the welfare of the people (the nation), the market state exists to maximize the opportunities [of its citizens],” largely through its ability to leverage capital for its people’s purposes. It’s worth noting that this vision of the “market state” doesn’t necessarily mean a replacement of government with markets or public purposes with private—but it does mean a change in the nature and purpose of government.

Current-day conservatives like to ignore that, even in an individualistic society, collective means of action are necessary. But liberals hate to admit that such collective means do not necessarily require a governmental—i.e., universal, monopolistic, and coercive—mechanism, and that is increasingly true with today’s technological developments. This more fluid world of changing roles also means, however, that there are roles governments themselves can—and arguably should—play beyond what has been conceived hitherto.

My favorite example of this has always been the post office. Twenty years ago, the U.S. Postal Service discovered it could make some extra money by offering services like copy machines and fancy wrapping paper to customers who were already there to mail papers and other items. Nowadays, the suggestions include selling coffee, Internet browsing, and even USPS clothing to patrons. Of course, various private companies offer similar services, so they got Congress to prohibit government competition. The ironies here are endless: A government entity could actually out-compete the private sector—not because of unfair cross-subsidization of prices, but because public goods supplied by government generally constitute a natural monopoly, and once a monopoly “backbone” is in place, it makes eminent sense to offer all sorts of “apps” from it. (Just ask Facebook.) This concept has been taken much further in other countries, where the post office provides all sorts of ancillary services—most notably in Japan, whose postal service not-illogically operates one of the world’s largest banks. In this country, however, Congress essentially prohibits USPS from competing like a business. Unsurprisingly, USPS is an unprofitable mess.