Quote from eusdaiki:
Consumption in the US has been the leading factor in the world's aggregated demand for many years. Today most countries export a big % of their production to the US.
If consumer spending in the US goes down, then you can expect exports to decline all over the world. Basically there's too much risk taken on the assumption that the US will do well.
If problems arise in the US economy, and consumer spending slows for an extended period of time. The nations that depend on US exports will go into an economic slowdown along with the US at first, but as they diversify their exports [basically looking for new markets] they might be able to accelerate their economies again or at least mitigate the effects of the US slowdown.
many of these countries are already attempting to diversify their exports, to other world powers like Europe, Japan, China, etc... but it's a slow process.