"If they decide that everyone needs to eat broccoli, " then the commerce clause could allow Congress to require everyone to buy a certain quantity of broccoli, the judge said.

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Australians voted overwhelmingly then to repeal a clause that had excluded aborigines from being counted in the census.

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It said that if the stand-off was not serious enough to invoke the clause, then it was difficult to imagine what could, "short of all out war".

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Then there is the interstate commerce clause.

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