Libertarians like Sen. Rand Paul (R-Ky.) have asserted that the NSA is violating the Fourth Amendment ever since leaks by former intelligence contractor Edward Snowden revealed the existence of the program this summer.

The Obama administration is also facing criticism from U.S tech companies and its own outside advisers on the threats against individual rights posed by secretive surveillance programs. Eight prominent U.S. tech giants jointly penned an open letter to the President and Congress demanding reforms to increase the transparency and accountability of secret data-collection efforts. A panel of outside advisors to President Obama has also recommended that NSA rules be changed to require a court order before accessing individuals’ telephone information.

Piling on, for the first time ever a federal judge recently ruled that the NSA program is likely unconstitutional, granting a preliminary injunction against the agency.

As all this brews, here are four things you should know about the NSA’s programs.

1) The NSA is collecting information about you

Based on what has gone public about the surveillance program, it is clear that the scale of ongoing NSA data collection is massive. Not only does the NSA indiscriminately collect telephone metadata on millions of Americans — information such as phone numbers, call locations and call durations — but also information from instant messaging accounts, personal email accounts and social networking sites like Facebook. The NSA has allegedly paid private companies like AT&T, Microsoft and Google millions of dollars for access to such information.

Suspected terrorists aren’t the sole targets of NSA data collection. We all are.

2)  The Supreme Court case relied on by the Department of Justice predates the cell phone

Multiple judges had previously upheld the surveillance program based on a 1979 case that permitted police to record the phone numbers dialed on a particular phone line without a warrant, but D.C. District Court Judge Richard Leon dismissed that decades-old ruling this week noting that it predated the rise of cell phones — not to mention the Internet.

“The ubiquity of phones has dramatically altered the quantity of information that is now available and, more importantly, what that information can tell the Government about people’s lives,” argued the judge.

For example, unlike 1970s phone lines, cell phones today can store contacts, send text messages and keep track of a user’s geographic location. The growing capabilities of mobile technology and the increasing role of cell phones in average Americans’ lives makes collected metadata much more intrusive into one’s private life than it was three decades ago.

The matter will almost certainly work its way back to the Supreme Court, where the Justices can revisit its 1979 decision against the backdrop of modern technologies like email, social networks and wireless communications.

3) There is no public instance of the NSA program preventing an imminent terror attack

Judge Leon doubted the constitutionality of the NSA program in part because the government did not “cite a single instance in which analysis of the NSA’s bulk metadata collection actually stopped an imminent attack.” In other words, there is no justifiable reason to indiscriminately collect information on all Americans if the government isn’t able to show the program is essential to our national defense.

The judge’s finding stands in contrast to the NSA chief’s claim that the surveillance efforts have helped prevent over 50 “potential terror events” since the 9/11 attacks in 2001. Due to the extreme secrecy of the NSA’s operations, it is difficult for the public to know with any certainty how important or successful the NSA’s programs have actually been.

4) There is already evidence of NSA abuse

The plaintiff who sued the NSA and won a preliminary injunction this week has alleged targeted harassment by the NSA, including the hacking of his personal email to send his contacts messages. This allegation is unproven, but previous abuse within the agency is well documented.

Earlier this year the NSA’s inspector general revealed that employees had been misusing the agency’s surveillance powers to spy on love interests. Back in 2008, NSA employees were caught eavesdropping on deployed U.S. Soldiers’ phone sex with spouses and girlfriends back home for their own amusement.

Many Americans may not mind the NSA’s subtle intrusion into their lives, but the drafters of our Constitution were rightly weary of consolidating great power within the hands of a few government officials. James Madison, largely considered the “Father of the Constitution,” is credited with noting that, “there are more instances of the abridgement of freedom of the people by gradual and silent encroachments by those in power than by violent and sudden usurpations.”

Is there any doubt what Madison might have thought about the NSA snooping through Americans’ Facebook accounts and email?