In 1975 the US had a trade surplus and hasn't seen one since and likely never will again.

After 1975, oil got really expensive... and scarce, for a while.

Thus was born the need and desire to outsource to reduce costs, not to mention the fear of Japan taking over (remember those days?)

Its all inter-related, isn't it? Foreign imports reduced costs on other goods that otherwise, if were fully borne by The American Consumer, would mean they'd build smaller houses and other things.

So, the economy shifted gears and outsourced a ton of manufacturing overseas... literally millions of tons of manufacturing, annually. I happen to live in a massive port city and can assure you that all those containers coming into North America are filled with products made thanks to oil, somewhere along the line.

How big? Well lets first think about the impact oil itself has on the trade deficit, as clearly the advent of peak oil in the US has had a major impact on the deficit froom the 70's onward - increasing it as oil had to be imported, and also forcing outsourcing to other locales with cheaper labour to avoid inflation and keep the consumer spending.

The "trade deficit" is a simple balance sheet - what's really instructive is to look at the GOODS only number, and factor out the trade surplus that exists in services, and also seperate the oil imports. Census.gov gives all the numbers:

Some selected years... getting tired:
Goods only surplus/deficit:
Year  Petroleum    Non Petroleum
1990  -54,513      -47,205
1991  -43,617      -21,781
1993  -44,002      -71,567
1994  -44,315     -106,314
1995  -48,059     -110,742
1996  -63,119     -107,095
1997  -61,352     -119,170
1998  -42,828     -186,931
1999  -59,187     -269,634 (cheap gas and Internet fever!)
2000  -108,266    -327,839
2001  -114,658    -329,393
2002  -111,230    -408,126
2003  -118,693    -448,538
2004  -126,466    -522,922

Going from a trade surplus of 12 billion in 75 to a trade deficit of 600 billion or more but it would be worse if not for the exports of services and goods. The point I'm trying to make is that within the the next few years an annual deficit of 1 trillion dollars in goods will be hit.

1 trillion in goods = a ton of oil which is not on the US balance sheet.