A year after whistleblower Edward Snowden revealed pervasive dragnet spying by the National Security Agency, Congress has finally begun to take action. Last night, the House “unexpectedly and overwhelmingly” voted in favor of a measure imposing two major limits on the NSA’s domestic dragnet. By a wide and revealing margin, 293 Representatives came together across party lines to approve an amendment to a military spending bill that — if ultimately signed into law after agreement in the Senate — could deny funding to two particular NSA abuses. First, the amendment aims to effectively prohibit NSA queries taking advantage of a “backdoor search loophole” (in which the NSA collects information about Americans by designating a foreigner with whom they communicate as the “target” of their search). It would also prohibit the NSA from building security vulnerabilities into tech products made in the US, as it has for “computers, hard drives, routers, and other devices from companies such as Cisco, Dell, Western Digital, Seagate, Maxtor, Samsung and Huawei.” Members of Congress from both major parties expressed the widespread popular outrage underlying the vote. According to a joint statement by Representatives Sensenbrenner (R-WI), Lofgren (D-CA), and Massie (R-KY), “Americans have become increasingly alarmed with the breadth of unwarranted government surveillance programs.” Rep. Massie also put it more colorfully, explaining that “The American people are sick of being spied on,” evoking the words of Rep. Tulsi Gabbard (D-HI), who sharply criticized “this dragnet spying on millions of Americans.” The House vote was something of a surprise. Only weeks before, after the House approved a watered-down version of the USA FREEDOM Act, gutted by the Obama White House and Republican House leadership after receiving bipartisan support and approval in two different House committees. Several members of Congress made clear that their support for this week’s amendments to the House Defense Appropriations bill (mirroring a similar, nearly successful effort last year along similar lines) was prompted by the co-optation of their earlier reform efforts. Sensenbrenner, for instance, was among the original sponsors of the PATRIOT Act and has said since the Snowden revelations that “if Congress had known what the NSA planned to do, the Patriot Act would not have passed.” He was among the original drafters of the USA FREEDOM Act, and joined by “other lawmakers[,] complained that the legislation didn’t go far enough, necessitating their amendment to the defense bill.” Other members of Congress who resisted earlier efforts to deny funding to the NSA’s domestic dragnet may have learned something from the experience of former House Majority Leader Eric Cantor, who lost a primary re-election vote shortly after helping to scuttle the USA FREEDOM Act. House Minority Leader Nancy Pelosi, in particular, has endured sustained criticism from constituents and changed her tune since last year‘s debate. Thursday’s vote shifts the landscape of the congressional debate, sending to the Senate a second set of proposed NSA reforms that better reflect the concerns of the American people. Even if successful, however, even this week’s amendments may not be enough to address even backdoor targeting, which itself represents only one among many problems. Wired magazine quotes “Matt Blaze, a computer science professor and cryptographer at the University of Pennsylvania,” who notes that “the scope…is limited. Even when the NSA and CIA don’t request or put pressure on vendors to incorporate backdoors, other agencies, like FBI, may be in the same business.” Indeed, as the Guardian quoted me as saying earlier this year, “The FBI’s history of abusing the civil liberties of Americans is longer even than the NSA’s.” Moreover, last night’s House amendment has yet to gain consensus in the Senate, where a battle over the co-opted USA FREEDOM Act was already brewing, nor does it have the blessing of the White House, which has intervened to scuttle congressional reform attempts before. Finally, even if ultimately enacted into law, last night’s amendments to the House Defense Appropriations bill would leave much of the NSA dragnet in place. Closing the back door search loophole and prohibiting the NSA from building security vulnerabilities into tech products are important goals. Yet other NSA programs (such as phone surveillance, weakly addressed by the USA FREEDOM Act) will remain in place until Congress finally conducts the kind of independent investigation that revealed decades of wanton crimes by US intelligence agencies only two generations ago, and finally takes action to force the agencies to justify the powers they gained using their unrelated failures before 9-11 as a pretext.