Interresting Toro,
Here is what i can add at the moment:
(NB: All i will be saying here can be traced back to wikipedia facts. just ask and i shall provide.)
(NB2: i still didn't read the thread on euro vs dollars myth, but we can still go ahead using facts)
The US dollars is the defacto standard trade currency. As you said, this means that all commodities prices are set in dollars. Again, as you said, transactions can be completed in other currencies, but it implies a currency conversion. It is for this reason that many countries maintain high reserves of US dollars, so that they can buy these commodities without the conversion peanlity. Again, as we said, the US dollars account for about 70% of the world reserve currency.
http://en.wikipedia.org/wiki/Reserve_currency
http://en.wikipedia.org/wiki/Dollar_hegemony
up to now, makes sense?
now, All these countries keeping the US dollars in reserve increases the US dollars value. This also makes the curreny very desireable for foreign investmens and stabilises it in the world. This explains why the USA can run such a high trade deficit without suffereing any visible impact. The dollars sustains a high trust value even in normally negative circumstances, because it is maintained through out the world and will not crumble as long as it is held and traded in high volumes.
http://en.wikipedia.org/wiki/Balance_of_trade
http://en.wikipedia.org/wiki/Petrodollar
again, makes sense?
Now, if, for any reason, the world starts trading commodities in another currency, such as the euro, this will have many countries transform their dollars reserve from US dollars to that new currency (notably euro). Again, they would do this to ensure they can trade commodities without any conversion impacts.
http://en.wikipedia.org/wiki/Petrodollar_warfare
http://en.wikipedia.org/wiki/Petroeuro
makes sense?
The thing is that if world countries transform their reserve currencies from dollars to euros, the dollar will lose its appeal and security and will begin behaving like any other normal currency. This would cause the USA to have to maintain a trade surplus, to ensure the sustained value of the dollar (and understand what canadians have to put up through :wink

. This would be caused by the fact that the dollar would no longer be held and traded in high volume, and would not be able to remain artificially interresting, due to the world owning it.
again, makes sense?
having to generate a trade surplus would be very hard for the USA, and unless some type of economic miracle is performed, it would be a VERY big hit for the economy (and standards or life). It is the reason why the enemies of the USA want so badly to trade oil in euros, because they know it is the best way to slay the dragon; by cutting its food.
http://en.wikipedia.org/wiki/Economy_of_usa
Again, makes sense?
now, the logical survival action for the USA is to use their current might to ensure that the dollars remains the dominant reserve currency. Doing this, they ensure they remain strong, before the fall occurs and another country such as china emerges and dominates. This would explain the apparent coincidence of the USA delivering freedom in the 3 countries that want the euro as the main reserve currency (and thanks to their oil, have the credibility to do so).
http://en.wikipedia.org/wiki/Petrodollar_warfare
http://www.energybulletin.net/7707.html
again,. does this make sense?
IF this reasoning is correct, then it is on par with the so called conspirative web sites i posted earlier. It would also force us to reconsider the euro vs dollars myth you were talking about. It certainly makes logical sense and doesn't look like a myth to me. Should you not be convinced, more facts will be searched for until we find the truth.
It would also explain why the US are doing all they can to quickly deliver democracy in iraqm iran and potentially venezuela, the 3 main countries that demonstrated a strong will to change from petrodollars to peroeuros. (knowing it would destroy their main enemy, the USA)
It is, in it self, a logical defense mechanism of the USA, and no one can claim it bad, since it is normal for them to try and maintain their survival. But, the bad part is how they lie to their people and claim to spead peace, while in fact they are using the lives of their soldiers for their own selfish advantage.
Now, as a canadian, i like you, would much rather the us dollars be the main reserve currency than the euro, but i think we must search for the truth, no matter how hard it is for us to accept. A US fall would also greatly hurt canada, and i certainly dont want that, but it doesn't stop us from trying to understand what is happening in our world...
i hope this helps and i certainly appreciate discussing with you guys, this is all very interresting..
