The President Has No Power to Ban People From Entering the Country
In the video below, Judge Andrew Napolitano explains why he thinks President Trump's Executive Order banning refugees and immigration from seven Middle Eastern countries is lawful, and that Judge James Robart and the Ninth Circuit Court of Appeals were being political in putting a freeze on the ban and in their hearing over whether that freeze should be repealed.
This video seems to have been recorded before the Ninth Circuit Court of Appeals denied the Trump administration's request for a stay on Judge Robart's decision.
Unfortunately for Judge Napolitano he gets this one completely wrong. He claims that foreign policy is the purview of the executive and as such the courts have no authority to counteract this particular Executive Order.
Article 2 of the Constitution spells out the powers of the President of the United States, but nowhere does it give the President the power to ban anyone from entering the country. The Constitution must explicitly enumerate the powers of the federal government otherwise the federal government does not have those powers, as per the Tenth Amendment to the Constitution.
The powers not delegated to the United States by the Constitution, nor prohibited by it to the States, are reserved to the States respectively, or to the people.
Furthermore, immigration is a domestic issue and not a foreign policy issue. Napolitano's argument that this ban is in the realm of foreign policy might be more convincing if the Congress had issued an official declaration of war, which is their right and responsibility per the Constitution, against any of the seven countries affected, but that is not the case. As the United States is not officially at war with Libya, Sudan, Somalia, Yemen, Iraq, Syria, or Iran it cannot be argued that President Trump's position as Commander-in-Chief gives him the authority to ban immigrants from those countries, let alone refugees from every country on the planet, from entering the United States.