There are 700,000 names on the United States' terrorist watch list

As reported by the New York Times:

"...the federal government’s main terrorist watch list has grown to at least 700,000 people, with little scrutiny over how the determinations are made or the impact on those marked with the terrorist label...

What’s more, the government refuses to confirm or deny whether someone is on the list, officially called the Terrorist Screening Database, or divulge the

criteria used to make the decisions — other than to say the database includes “individuals known or suspected to be or have been engaged in conduct constituting, in preparation for, in aid of, or related to terrorism and terrorist activities.”

Even less is known about the secondary watch lists that are derived from the main one, including the no-fly list (used to prevent people from boarding aircraft), the selectee and expanded selectee lists (used to flag travelers for extra screening at airport checkpoints), the TECS database (used to vet people entering or leaving the United States), the Consular Lookout and Support System (used to screen visa applications) and the known or suspected terrorists list (used by law enforcement in routine police encounters)...  

“It makes no sense that people who have not actually been accused of any wrongdoing can’t challenge” their inclusion on a watch list.

More at the link.