Comment by rocqua

https://travel.state.gov/content/travel/en/us-visas/tourism-...

It states regarding a visa: "A visa allows a foreign citizen to travel to a U.S. port-of-entry (generally an airport) and request permission to enter the United States. A visa does not guarantee entry into the United States.

The Department of Homeland Security (DHS), U.S. Customs and Border Protection (CBP) officials at the port-of-entry have authority to permit or deny admission to the United States. "