Civil liberties advocates on the left and the right have argued for many years—but especially in the aftermath of revelations this year by former NSA contractor Edward Snowden—that spying by the National Security Agency disregards privacy protections outlined in the Fourth Amendment and is surely unconstitutional. Indeed, as the American Civil Liberties Union has argued, the NSA’s “unconstitutional surveillance” represents “a grave danger to American democracy.”

Now, a federal judge has recognized the constitutional concerns.

“I cannot imagine a more ‘indiscriminate’ and ‘arbitrary invasion’ than this systematic and high-tech collection and retention of personal data on virtually every single citizen for purposes of querying it and analyzing it without judicial approval,” wrote US District Judge Richard Leon.

Judge Leon’s decision, which will surely be appealed, focuses attention on legal challenges to the spying program. But it also serves as a reminder that Congress can and should act to defend privacy rights.

“The ruling underscores what I have argued for years: The bulk collection of Americans’ phone records conflicts with Americans’ privacy rights under the U.S. Constitution and has failed to make us safer,” says Senator Mark Udall, D-Colorado, a supporter of legislation to end the bulk collection program. “We can protect our national security without trampling our constitutional liberties.”

Senator Ron Wyden, D-Oregon, said: “Judge Leon’s ruling hits the nail on the head.  It makes clear that bulk phone records collection is intrusive digital surveillance and not simply inoffensive data collection as some have said. The court noted that this metadata can be used for ‘repetitive, surreptitious surveillance of a citizen’s private goings on,’ that creates a mosaic of personal information and is likely unconstitutional. This ruling dismisses the use of an outdated Supreme Court decision affecting rotary phones as a defense for the technologically advanced collection of millions of Americans’ records. It clearly underscores the need to adopt meaningful surveillance reforms that prohibit the bulk collection of Americans’ records.”

The senators had reason to be enthusiastic about Judge Leon determination that legal challenges to the massive surveillance program are valid. So valid, in fact, that he issued a preliminary injunction against the program. The judge suspended the order, however, in order to allow a Justice Department appeal.

But Judge Leon was blunt regarding the strength of the challenge that was brought after Snowden revealed details of the agency’s spying in The Guardian.

"I have little doubt that the author of our Constitution, James Madison… would be aghast," the judge wrote with regard to the NSA program for surveillance of cell phone records,

“The court concludes that plaintiffs have standing to challenge the constitutionality of the government’s bulk collection and querying of phone record metadata, that they have demonstrated a substantial likelihood of success on the merits of their Fourth Amendment claim and that they will suffer irreparable harm absent…relief,” Judge Leon wrote in response to a lawsuit brought by Larry Klayman, a former Reagan administration lawyer who now leads the conservative Freedom Watch group.

The case is one of several that have been working their way through the federal courts since Snowden disclosed details of the NSA program.

Legal challenges to NSA spying are not new, and they have failed in the past.

Challenging the FISA Amendments Act (FAA)—the law that permits the government to wiretap US citizens communicating with people overseas—Amnesty International and other human rights advocates, lawyers and journalists fought a case all the way to the US Supreme Court in 2012. In February 2013, however, the Justices ruled 5-4 that the challengers lacked standing because they could not prove they had been the victims of wiretapping and other privacy violations.

The Justice Department has continued to argue that plaintiffs in lawsuits against the spying program lack standing because they cannot prove their records were examined. But Judge Leon suggested that the old calculus that afforded police agencies great leeway when it came to monitoring communications has clearly changed.

Suggesting that the NSA has relied on “almost-Orwellian technology,” wrote Judge Leon, who was appointed by former President George W. Bush to the United States District Court for the District of Columbia bench. “The relationship between the police and the phone company (as imagined by the courts decades ago)…is nothing compared to the relationship that has apparently evolved over the last seven years between the government and telecom companies.”

The judge concluded, “It’s one thing to say that people expect phone companies to occasionally provide information to law enforcement; it is quite another to suggest that our citizens expect all phone companies to operate what is effectively a joint intelligence-gathering operation with the government.”

This case will continue in the courts, as will others.

But it is also in Congress. A left-right coalition that extends from Congressmen Justin Amash, a libertarian-leaning Republican, to Congressman John Conyers, a progressive Democrat, has raised repeated challenges to the NSA spying regimen.

Now, Congress needs to step up to what Congressman Alan Grayson, D-Florida, refers to as “the spying-industrial complex.”

A number of members are ready. Vermont Senator Bernie Sanders responded to Judge Leon's ruling by saying: “In my view, the NSA is out of control and operating in an unconstitutional manner. Today’s ruling is an important first step toward reining in this agency but we must go further. I will be working as hard as I can to pass the strongest legislation possible to end the abuses by the NSA and other intelligence agencies.”

The outlines for legislative action have already been presented by the American Civil Liberties Union and other groups that work on privacy issues.

“Congress should not be indifferent to the government’s accumulation of vast quantities of sensitive information about American’s lives,” Jameel Jaffer, the ACLU’s deputy legal counsel told the House Judiciary Committee in July. “This Committee in particular has a crucial role to play in ensuring that the government’s efforts to protect the country do not compromise the freedoms that make the country worth protecting.”

Jaffer told the committee,

Because the problem Congress confronts today has many roots, there is no single solution to it. But there are a number of things that Congress should do right away:

• It should amend Sections 215 and 702 to expressly prohibit suspicionless or “dragnet” monitoring or tracking of Americans’ communications.

• It should require the executive to release basic information about the government’s use of foreign-intelligence-surveillance authorities, including those relating to pen registers and national security letters. The executive should be required to disclose, for each year: how many times each of these provisions was used, how many individuals’ privacy was implicated by the government’s use of each provision, and, with respect to any dragnet, generalized, or bulk surveillance program, the types of information that were collected.

• Congress should also require the publication of FISA court opinions that evaluate the meaning, scope, or constitutionality of the foreign-intelligence laws. The ACLU recently filed a motion before the FISA court arguing that the publication of these opinions is required by the First Amendment, but Congress need not wait for the FISA court to act. Congress has the authority and the obligation to ensure that Americans are not governed by a system of secret law.

•  Finally, Congress—and this Committee in particular—should hold additional hearings to consider further amendments to FISA, including amendments to make FISC proceedings more transparent.

Members of Congress, conservatives and liberals, Republicans and Democrats, have moved on a number of these fronts. Now it is time for concerted action.

The Congress does not have to wait for the legal wrangling to be resolved. It can, and should, act in defense of civil liberties.