Neal, from what I researched a while back, the nutshell of the Marshal plan was this.
First, it was money along with goods. LOTS of money. And all in US Dollars. It was given as a GIFT. Not a loan. The thing with loans is they have to be repaid. Gifts or grants - not so much. Now, it's all honkydory but when you have a lot of dollars,and the US economy struggles - what you do with dollars is you sell them off. Or lend somehwere else - i.e. Russia in late 80s and early 90s. On the same token, you have millions of dollars that was carried by the US military during the WW2 that was left in europe (remember all them little sports car they brought back home, the alfas, etc..) Now, that money stays in Europe, but it MUST come back tot he US. And when you have the BrettonWoods that says that in foreign exchange the US dollar is an equivalent of gold - you want to return them sooner or later. When France did exactly that, the US ended up cancelling the system, and for the first time we ended up with world currency that was ...paper. It was not money. Around that time we started to descend into the use of derivatives of creating wealth, and by 80s it was the Wall Street time when everyone wanted to Charlie Sheen and Michael Douglas (j/k). But actually that time was very crucial in mid 70s because instead of creating wealth by means of production and real assests, we switched to using financial instruments to creat wealth. And to make the long story short, that's why we no longer have the prospering economies - because we live in debt, because the rules of capitalism do not apply to 'fake' wealth creating and borrowing from future to sustain our own growth. If you can't afford a car in 60s - may be you don't buy it. YET, today many own one despite not being able to really afford it. You see these people switch to bikes when an oil crisis comes.
Anyway, it's much much big subject to discuss, but Marshall Plan was good and it was also a great scheme that the US used to export all the extra money it printed during the WW2 to finance the war effort. But the economy didn't have to observe the huge money supply - because it was 'exported' as a Marshall Plan to the nations that recieved it.
When the dollar collapsed back in the early 70s, guess which European countries DID NOT suffer from it? That's right, the ones who didn't accept the plan. One such country was Finland (and when I say did not accept i mean the gigantic monetary gifts). When Stalin forbid Warsaw pact countries from accepting it, this was one of the reasons it's argued - he didn't want the us dollar to be poured into those economies (or perhaps his advisors didn't want to). Of course the Marshall Plan is credited for rebuilding Europe. But it should also be credited for preventing a hyper post war inflation in the United States.
Which actually is connected to the Iraq and USA war. One of the things Iraq did in 2002 was to switch to Euro in all of its oil transactions, one of the first if not THE first arab oil exporter. That in long run would have hurt the US Dollar, as other arab countries might have followed suit. Europe trades a lot with arab countries. It is argued that it was one of many little reasons that added up to the Iraq war (argued more in Finance and Economics classes probably, and not so much in the Media. WMD are more interesting to the regular Joe than some foreign transaction currency mambojumbo).