Further developments with Trump's seven-country ban:
http://www.cbc.ca/news/world/trump-immigration-executive-order-visas-muslim-countries-1.3966482US District Judge James Robart (a GW Bush appointee) has issued a nationwide hold against enforcing the ban while challenges against it proceed through the courts.
http://www.cbc.ca/news/politics/pre-clearance-trump-ban-1.3965666The order, should it continue to be enforced, whether by ultimately being found to be legal and constitutional or should the Trump administration direct Customs and Border Control officers to ignore judicial stays, may impact pre-clearance arrangements the US has with various countries or jurisdictions: Canada, Ireland, Aruba, the Bahamas, Bermuda, and the United Arab Emirates.
In particular, in Canada, US customs agents carry out customs checks at certain airports and other points of departure (specifically Halifax, Montreal, Ottawa, Toronto, Winnipeg, Calgary, Edmonton, and Vancouver airports, along with the Port of Vancouver, the Pacific Central train station in Vancouver, and certain ferries between BC and Washington state; a bill passed by the US Congress in December is set to extend the arrangement to Montreal's Central Station, the Toronto Island airport, and the Quebec City airport), which allow people traveling from Canada to land directly at smaller US airports that do not have their own customs facilities. Because the checks are being made on Canadian soil, not extraterritorial US soil, they must be done in compliance with Canadian law and the Constitution of Canada.
If Trump's executive order were enforced at pre-clearance facilities in Canada, any Canadian resident thus discriminated against could sue in a Canadian court or human rights tribunal, and if the ban were found to be inconsistent with Canadian law, US officials would still be required to enforce the ban, per US law, while Canadian police would be required to prevent them from enforcing the ban, per Canadian law.
The Irish government has also expressed concerns about the ban, and the Dutch government, which had been seeking a pre-clearance arrangement for Schiphol international airport, near Amsterdam, cancelled talks to reach such an agreement.
tl;dr: A judge has ordered Trump's travel ban to be temporarily unenforceable; it remains to be seen if the administration will respect the order. Meanwhile, the ban could play havoc with pre-clearance arrangements the US has with certain other countries, in particular with Canada.
