What if the NSA's surveillance isn't legal? What if its collection of phone records and its electronic surveillance of foreigners and Americans violates the letter of the laws that the agency cite as its newfound authority, the Patriot Act and the Foreign Intelligence Surveillance Act? We'd be where we are now, with the government relying on unprovable arguments for efficacy instead of demonstrable legal rationalization.

We know that in at least two moments the NSA programs likely violated federal law. In a secret ruling, the Foreign Intelligence Surveillance Court, the body tasked with approving the government's surveillance requests, determined that the NSA's data collection violated the Fourth Amendment. Then, of course, there was the period before the passage of the amendments to FISA in 2008. As documents released by the Guardian Thursday make clear, the NSA's surveillance at least in some ways pre-dates its explicit legal authority to do so.

In an opinion piece in The New York Times today, two legal experts argue that even that expansion may not have been enough. The two, Jennifer Stisa Granick of Stanford and Christopher Sprigman from the University of Virginia, first argue that the bulk collection of phone records under the Patriot Act exceeds the legal boundaries. "[A]ny data might be 'relevant' to an investigation eventually," they write, "if by 'eventually' you mean 'sometime before the end of time.'" But their stronger critique is of the PRISM / electronic data surveillance under FISA. The 2008 amendments state that the NSA can't "intentionally acquire any communication as to which the sender and all intended recipients are known at the time of the acquisition to be located in the United States."

How could vacuuming up Americans’ communications conform with this legal limitation? Well, as James R. Clapper Jr., the director of national intelligence, told Andrea Mitchell of NBC, the N.S.A. uses the word “acquire” only when it pulls information out of its gigantic database of communications and not when it first intercepts and stores the information.

If there’s a law against torturing the English language, James Clapper is in real trouble.

Prior to the passage of the amendments, the government relied on its own legal interpretations of existing mandates to justify its actions. As Thursday's leaks made clear, the push for more data collection in the wake of September 11th preceded the legal rationales used to justify them. Once the NSA began partnering with domestic law enforcement in 2004, even the NSA balked at the government's shaky legal analysis. Granick and Sprigman note that the primary justification came then and comes now from "select Supreme Court cases, decided before the era of the public Internet and cellphones." (Update, 11:20 a.m.: A group of 26 senators has called on Clapper to answer questions about the data collection.)

The FISA court seems to be taking steps to drop the wall of privacy behind which it acts, however minimally. Earlier this month, it ruled that that it wouldn't block release to advocacy groups of that secret ruling on the Fourth Amendment violations. On Wednesday, CNet reported that it was also willing to allow tech companies to provide more information about government requests for user data.

[Reggie] Walton, the FISC's presiding judge, gave the Justice Department until July 9 to respond to the requests from Google and Microsoft to disclose summary statistics about orders received under Section 702 of the FISA Amendments Act, which became [law] in 2008. The pair of companies have until July 16 to submit their replies.

Allowing these companies to reveal the extent of request form the government would provide a very limited amount of information about the government's activity — but it would at least offer some.

The NSA either can't or won't crack the door in that way. Its response to critique has instead been to argue that its surveillance systems are essential to keeping Americans safe, an argument that relies heavily on secret data concerning disrupted terror activity. And, worse, that revealing information about its activity strengthens terrorists.

As documented in an exceptional piece by Jack Shafer at Reuters, the agency did a brief tour of major media outlets earlier this week, arguing that the leaks by Edward Snowden and the reporting by the Guardian prompted terrorists to change their behavior.

The media tour included Reuters, which had a similar conversation with “two U.S. national security sources.” Its piece, time-stamped two hours after CNN’s, reported that “militants have begun responding by altering methods of communication.” Like CNN, Reuters learned from the intel officials that both Sunni and Shi’ite groups had changed communications methods and that those changes might leave the U.S. blind to future attacks.

We've noted before that this cannot be proven, one way or the other. It's possible that the inability to prove those shifts plays to the NSA's detriment, making it hard for the agency to make its case that its tools are necessary to protect us, legal or not. But a skeptic is warranted in assuming that the inability to share information on the tools' efficacy plays to the NSA's advantage. That argument was made very eloquently and directly by Chris Hayes on his MSNBC program last night.

"There is a vast and growing web of secret government in this country," Hayes concluded. "And it simply cannot be the case — it is not acceptable — that the only things we know about it are the things the members of that secret government want us to know."

So much happens in government on an hourly basis that we tend to give it the benefit of the doubt. Even those who are skeptical of the federal government — or who are openly hostile to it — don't spend extended time worrying about all of the various behaviors of the government on our collective behalf. We ask our legislators and elected officials to represent our will and protect our needs. In this case, those legislators are largely complicit in the authorization of the NSA's activity — and are also dependent on the secret government agencies for information on what's happening.

So, what if the NSA's surveillance isn't legal? For now, the only answer seems to be: Trust us. And, sorry, but you can't verify.

Photo: NSA head Keith Alexander meets the press. (AP)