Today for only the 19th time in history, the US government has found itself in a "funding gap", a technical term for shut down. One of the reasons why this event is not being taken too seriously by the financial punditry, markets or much of the media, is that looking back not only have most government shutdowns been brief affairs, lasting less than 10 days - with the occasional outliers, such as the 21-day closure in 1995 and the 16-day halt in September 2013 - they have had little to no impact on either the market or the economy.

And yet, as Goldman writes, after the two political parties breached the shutdown Rubicon, there is a distinct possibility that this time the shutdown lasts "a few weeks" if not longer. The reason is one of both optics and motives: according to Goldman's political economist Alec Phillips, "both sides appear to think they could gain from a [lengthy] shutdown."  He explains: