Good article, I have just one comment to add to it, and one mild criticique.
Comment: I find it amusing those on the right wing who find the increase in the percentage of income tax paid by the top 1-2% in the last 20 year or so in the United States horrifying. For some reason they never mention that the primary reason the top 1-2% pay so much more is because they've chosen to take so more much of the 'pie' for themselves. I always respond to them "if they want to stop paying so much in taxes they can choose to pass on some of their earnings to their employees."
Criticism: Similarly, (top) U.S. marginal tax rates were above 90 per cent in the 1950s -- a decade of strong U.S. economic growth.
This is actually a myth. The 1950s were actually a decade of pretty much stagnation in the U.S. The wonderful website www.meaursingworth.com has a calculator that shows growth rates. Real GDP per capita measured a rather weak 1.22% from 1951 to 1960.
However, Linda McQuaig's point is still correct though. Even after Kennedy lowered the top marginal tax rate it was still 70% and growth was very strong in the 1960s. According to measuring worth Real GDP per capita grew at a robust rate of 3.13% from 1961-1970.