The prospect of American Courts deferring to foreign laws and customs in rendering decisions which impact our life is so chilling, so alien and so evil that any measures whatsoever to frustrate this are acceptable.
And I think Sam Adams, George Washington and Thomas Paine would agree.
Actually, in those early days we often looked to British court because our courts hadn't built up much precedent. And we still do it. The recent McDonald majority decision cited Blackstone, a British judge who died around the time of our revolution, on the issue of the right to self defense.