There is always a lot of confusion about this expression. A pike is an old weapon like a spear with an axehead on it so I think the original idea meant that you were at the sharp end of an ugly stiuation. The modern equivalent of staring down the barrel.
Pike is also an american word for a type road and I think that caused confusion along with the fact that the expression is often used to mean coming 'down the pipeline' (in fact I've heard some americans interchange 'down the pike' and 'down the pipe')
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