"Every single European country is signed up to this, they are utterly unanimous in their determination to fight the downturn in this way, " Brown told reporters.
Mr Samuelson's determination to provide a unified approach to macroeconomics created a false sense that there was a single way of thinking about how economies work.
Another group demonstrating demands, with more determination than expectation, that if "Obamacare" is killed it should be replaced with a single-payer system.