The US government’s web of surveillance is vast and interconnected. Now we know just how opaque, inefficient and discriminatory it can be.

As we were reminded again just this week, you can be pulled into the National Security Agency’s database quietly and quickly, and the consequences can be long and enduring. Through ICREACH, a Google-style search engine created for the intelligence community, the NSA provides data on private communications to 23 government agencies. More than 1,000 analysts had access to that information.

This kind of data sharing, however, isn’t limited to the latest from Edward Snowden’s NSA files. It was confirmed earlier this month that the FBI shares its master watchlist, the Terrorist Screening Database, with at least 22 foreign governments, countless federal agencies, state and local law enforcement, plus private contractors.

The watchlist tracks “known” and “suspected” terrorists and includes both foreigners and Americans. It’s also based on loose standards and secret evidence, which ensnares innocent people. Indeed, the standards are so low that the US government’s guidelines specifically allow for a single, uncorroborated source of information – including a Facebook or Twitter post – to serve as the basis for placing you on its master watchlist.

Of the 680,000 individuals on that FBI master list, roughly 40% have “no recognized terrorist group affiliation”, according to the Intercept. These individuals don’t even have a connection – as the government loosely defines it – to a designated terrorist group, but they are still branded as suspected terrorists.

The absurdities don’t end there. Take Dearborn, Michigan, a city with a population under 100,000 that is known for its large Arab American community – and has more watchlisted residents than any other city in America except New York.

These eye-popping numbers are largely the result of the US government’s use of a loose standard – so-called “reasonable suspicion” – in determining who, exactly, can be watchlisted.

Reasonable suspicion is such a low standard because it requires neither “concrete evidence” nor “irrefutable evidence”. Instead, an official is permitted to consider “reasonable inferences” and “to draw from the facts in light of his/her experience”.

Consider a real world context – actual criminal justice – where an officer needs reasonable suspicion to stop a person in the street and ask him or her a few questions. Courts have controversially held that avoiding eye contact with an officer, traveling alone, and traveling late at night, for example, all amount to reasonable suspicion.

This vague criteria is now being used to label innocent people as terrorism suspects.

Moreover, because the watchlist isn’t limited to known, actual terrorists, an official can watchlist a person if he has reasonable suspicion to believe that the person is a suspected terrorist. It’s a circular logic – individuals can be watchlisted if they are suspected of being suspected terrorists – that is ultimately backwards, and must be changed.

The government’s self-mandated surveillance guidance also includes loopholes that permit watchlisting without even showing reasonable suspicion. For example, non-citizens can be watchlisted for being associated with a watchlisted person – even if their relationship with that person is entirely innocuous. Another catch-all exception allows non-citizens to be watchlisted, so long as a source or tipster describes the person as an “extremist”, a “militant”, or in similar terms, and the “context suggests a nexus to terrorism”. The FBI’s definition of “nexus”, in turn, is far more nebulous than they’re letting on.

Because the watchlist designation process is secret, there’s no way of knowing just how many innocent people are added to the list due to these absurdities and loopholes. And yet, history shows that innocent people are inevitably added to the list and suffer life-altering consequences. Life on the master watchlist can trigger enhanced screening at borders and airports; being on the No Fly List, which is a subset of the larger terrorist watchlist, can prevent airline travel altogether. The watchlist can separate family members for months or years, isolate individuals from friends and associates, and ruin employment prospects.

Being branded a terrorism suspect also has far-reaching privacy implications. The watchlist is widely accessible, and government officials routinely collect the biometric data of watchlisted individuals, including their fingerprints and DNA strands. Law enforcement has likewise been directed to gather any and all available evidence when encountering watchlisted individuals, including receipts, business cards, health information and bank statements.

Watchlisting is an awesome power, and if used, must be exercised prudently and transparently.

The standards for inclusion should be appropriately narrow, the evidence relied upon credible and genuine, and the redress and review procedures consistent with basic constitutional requirements of fairness and due process. Instead, watchlisting is being used arbitrarily under a cloud of secrecy.

A watchlist saturated with innocent people diverts attention from real, genuine threats. A watchlist that disproportionately targets Arab and Muslim Americans or other minorities stigmatizes innocent people and alienates them from law enforcement. A watchlist based on poor standards and secret processes raises major constitutional concerns, including the right to travel freely and not to be deprived of liberty without due process of law.

Indeed, you can’t help but wonder: are you already on the watchlist?