Guest, the issue of the amount of oil has been dealt with in previous ANWR threads. Suffice it to say that IF ANWR holds significant amounts of recoverable oil it can make a dent in the severe unbalance of trade.

As far as 'saving' the oil until we really really need it, remember:
1) The pipeline is already thirty years old. It will probably not last another thirty years.

2) By the time we are desperate, the environmental lobby may be so weakened that development will occur with few environmental regs and little or no oversight.