Congress shall make no law respecting an establishment of religion, or prohibiting the free exercise thereof; or abridging the freedom of speech, or of the press; or the right of the people peaceably to assemble, and to petition the Government for a redress of grievances.
Here's the Oath of Office that the President must swear to as is prescribed by the Constitution in Article II, Section 1, Clause 8:
I do solemnly swear (or affirm) that I will faithfully execute the Office of President of the United States, and will to the best of my Ability, preserve, protect and defend the Constitution of the United States.
The Constitution then is the highest law of the land and it is the foremost duty of the President to protect it. A President obviously must understand it and know what would be constitutional and what wouldn't. It's his job.
So does John McCain know that his good friend, Reverend Rod Parsley, thinks that the purpose of the United States is to destroy Islam?
That's unconstitutional, right? If the United States set out to destroy a religion, that would be against the First Amendment, wouldn't it? There's no way John McCain would align himself with such anti-American views as that, right? The Constitution is America. The freedoms outlined in it are what America is about and has been from the beginning.
Does John McCain know the First Amendment of the Constitution of the United States? I don't think he does.
Maybe someone should tell him...