Here. It's very interesting. They're discussing lend-lease agreements in 1941. It seems to me to be pretty typical of Keynes - there's always a lot of thinking going on underneath the surface that doesn't get revealed unless you push a little deeper. Keynes is hesistant here because there's no naivete on his part about what certain statesmen can do in the interest of nationalism with ostensibly liberalized policies. Acheson acknowledges this further down in the passage. You can also clearly see Keynes's thought processes on the post-war international monetary system at this early stage. He seems primarily concerns that claims about non-discrimination won't stand in the way of his bancor and trade stabilization plans.
UPDATE: And I don't want to be exclusively positive. This is always a real liability for Keynes too. There is a much deeper argument behind things like "burying banknotes" that a lot of people miss because he either says things cryptically or he just has outbursts like the one with Acheson. Sometimes the outbursts get fleshed out in more detail later... but if they don't it can really obstruct peoples' understanding of what he's saying.