The table of figures is on the surface accurate but is essentially innacurate. For example the US did indeed spend 5.1% of GDP on defense in 1950, which was the last peacetime year before the Korean war broke out. US defense spending rose to 7.4% in 1951 and 13.2% in 1952, peaking at 14.2% in 1953 and 13.1% in 1954, 10.8% in 1955, only falling below 10% in 1960.

Here is a link to a longer-term study of US defense budget expenditures which offer more complete data: http://www.truthandpolitics.org/military-relative-size.php

Another curious artifact of the table data is that US defense expenditures in 1950, 1960, and 1980 tend to mark low points in expenditure, which also tend to make the table you posted misleading.

One could argue about 1960 (expenditure declined from 1959 and rose in 1961, but then resumed a slow decline until 1966 when it rose sharply. 1979/80 marked another low point.

But that is missing the forest for the trees. I think two of the most interesting years in the data are 1940 and 1948. US defense spenfing as a percent of GDP was 1.7% in 1940 and 3.5% in 1948. It would be interesting to see what expenditure levels were during the 30#'s but the data isn't there. I suspect that the US was spending was significantly lower than 1.7% during the 30's - they were already greaing up in 1940 though it was much swifter in 1941 and of course all through WWII.

The figures between 1945 and 1948 show a classic pattern for the US, I suspect data between 1865-1868 and 1918-1920 showed a similar pattern. The US historically has geared way up for a major war, then the armies demobilised and defense spending fell to very little, and that pattern was clearly being followed until 1948. In fact 3.5% (although only 10% of the 1945 level) was perhaps a little high, perhaps reflecting the 'tar baby' nature of post-war Europe, and Japan also. The US could not simply pack up and go home this time, things were more complex.

Then expenditures actually rose to 4.|% in 1949 and 5.1% in 1950! This is a clear and obvious effect of the establishment of NATO.

I think the US *natural* level of defense spending over the years prior to 1940 can be considered as no higher than 2% of GDP. Strategically the US has no threats on it's borders stronger than Mexican bandits, so maintaining a large enough navy to keep the British respectful and a cadre of an Army had been enough. So the argument advanced by Col Millen has this much credence; NATO was a major change in traditional US defense policy and surely the US negociated a quid pro quo with Europe in signing NATO?

In fact there is over evidence of that. I read Tony Judt's 'Postwar: A History of Europe Since 1945', where he spends a chapter on the birth of NATO. I can't quite directly but as I recall Professor Judt's analysis supports many of the points Col Millen made, although I doubt Judt would go quite as far as Col Millen did.

The bottom line is that Col Millen is substantially correct - the European powers did in fact offload a significant portion of their defense expenditurwe onto the shoulders of the US taxpayer in 1948. That is perhaps understandable, but the subsidy continued after 1960 when Europe had completely recovered and in fact accellerated after the fall of the Berlin Wall.