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If national policy is right and just, (as it should be),

..and the actions of leaders and officials is right, just and legal,

…why would Chief Justice Roberts be concerned there might be an avenue to challenge such policies?

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If our policy is not just, ...if our leaders actions, ...or the actions of our officials is not legal,
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…why shouldn't they be open to challenge?
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You can bet if a Canadian Mounted police shot an American that was on US soil, 

…John Roberts would expect to be able to seek redress.
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We are not isolationists.  We aren't an island unto ourselves.
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John Roberts shouldn't be able to arbitrarily impel the nation to conform only to his wishes.
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Legislation can provide a check against the activist judge.
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