In September 1998, during the depths of the Asian financial crisis, AlanGreenspan, the United States Federal Reserve’s chairman at the time, had asimple message: the US is not an oasis ofprosperity in an otherwise struggling world. Greenspan’s point is even closerto the mark today than it was back then.

Yes, the USeconomy has been on a weak recovery trajectory over the past three years. Butat least it’s a recovery, claim many – and therefore a source of ongoingresilience in an otherwise struggling developed world. Unlike the GreatRecession of 2008-2009, today there is widespread hope that America has the capacity to stay the course and provide a backstop for the rest of the world in the midst ofthe euro crisis.

Think again. Since the first quarter of 2009, when the US economy was bottoming out after its worst postwar recession,exports have accounted for fully 41% of the subsequent rebound. That’s right:with the American consumer on ice in theaftermath of the biggest consumption bingein history, the USeconomy has drawn its sustenance disproportionately from foreign markets. Withthose markets now in trouble, the US could be quick to follow.

Three regions have collectively accounted for 83% of America’s export-led growth impetus over thepast three years – Asia, Latin America, and Europe.(Since regional and country trade statistics assembled by the US Department ofCommerce are not seasonally adjusted, all subsequent comparisons are presentedon the basis of a comparable seasonal comparison from the first quarter of 2009to the first quarter of 2012.)

Not surprisingly, Asia led the way,accounting for 33% of the total USexport surge over the past three years. The biggest source of this increasecame from the 15-percentage-point contribution of Greater China (the People’sRepublic, Taiwan, and Hong Kong).  Needless tosay, China’s unfolding slowdown – even under the soft-landingscenario that I still believe is most credible – is takinga major toll on the largest source of America’s export revival. Theremainder of the Asian-led US export impetusis spread out, led by South Korea, Japan,and Taiwan – all export-ledeconomies themselves and all heavily dependent on a slowing China.

Latin America provided the second-largest source of America’s export resurgence, accounting for another 28% of thetotal gains in US foreign sales over the past three years. Brazil and Mexico collectively accounted for19 percentage points of that increase. Growth in both economies is now slowingsignificantly, especially in Brazil.But, given the close linkages between Mexican production and US consumption (which is now sputtering again), any resilience in the Mexicaneconomy could be short-lived.

Finally, there is the sad case of Europe,which has accounted for 21% of the cumulativegrowth in US exports over the past three years. Here, the US CommerceDepartment statistics are not as helpful in pinpointingthe source of the impetus, because only a partial country list is published.What we do know is that the United Kingdom,Germany, and France – the so-called core economies –collectively accounted for just 3.5% of total USexport growth since early 2009, with the UK grabbing the bulk of thatincrease. That suggests that most of America’s European export gain wasconcentrated in the region’s so-called peripheraleconomies. And that is clearly a serious problem.

Forecasts are always hazardous, butsome “what-if” scenarios shed considerablelight on what all of this means for the world’s largest economy. Since thesecond quarter of 2009, US annualized realGDP growth has averaged 2.4%. With roughly 40% of that increase attributable toexports, that means the remainder of the economy has grown at an anemic 1.4% pace.

Under a flat-line export scenario, with no rise in US exports, and ifeverything else remains the same (always a heroicassumption), overall real GDP growth would converge on that 1.4% bogey. That is a weak growth trajectory by anystandard – likely to result in rising unemployment and further deterioration inconsumer confidence.

Alternatively, in a moderate export-downturn scenario, with real exportsfalling by 5% over a four-quarter period, real GDP growth could slip below the1% “stall speed” threshold – leaving the USeconomy vulnerable to a recessionary relapse.By way of reference, the assumption of a 5% export downturn pales in comparison with the precipitous 13.6% decline in real exports thatoccurred in 2008-2009. As such, this “what if” is a cautiously optimisticassessment of the downside risks stemmingfrom weak external demand.

All of this underscores one of the more obvious, yet overlooked,implications of an increasingly interdependent world: we are all in ittogether. The euro crisis is a serious shock, and is now producing ripple effects aroundthe world. Europe is export-led China’slargest source of external demand; as Chinagoes, so goes the rest of China-centric Asia; and, from there, the ripplesreach the shores of an increasinglyexport-dependent USeconomy. As recent weakness in employment and retail sales suggests, that mayalready be happening.

Greenspan’s warning in 1998 came at a time when US exports accounted for only about10.5% of GDP. Today, that share stands at a record-high 14%, as post-crisis America hasmade a big bet on an export-led revival. The current global slowdown is not on a par with what occurred in the late 1990’s or the more wrenchingshocks of 3-4 years ago – at least not yet. But today’s global downturn canhardly be dismissed as unimportant for the US oranyone else.

In an era of globalization, there are no innocent bystanders.There are certainly no oases of prosperityin the face of yet another major shock in the global economy. America’s growth mirage is an important case in point.