After an unexpected and widely-supported bipartisan effort to rein in the National Security Agency's domestic surveillance powers, an amendment which would have stopped the agency from collecting the phone records of millions of Americans was narrowly defeated in a 205 to 217 vote in the House of Representatives.

Led by Michigan Congressman Justin Amash, the amendment was attached to an annual defense budget bill, seeking to defund the NSA's "ongoing, daily" collection of Americans' phone records under Section 215 of the Patriot Act. The effort had gathered an impressive outpouring of support from both sides of the aisle after passing the House Rules Committee on Monday, causing panicked responses from the Obama administration and the intelligence community.

The high-speed debate on the House floor, while brief, marked the first formal and open deliberation on the issue in Congress since a classified court order revealed that the NSA seizes domestic phone records under secret interpretations of the Patriot Act. "To think that the Congress has substantial oversight of this program is simply incorrect," said Rep. Zoe Lofgren (D-CA), who has previously criticized the NSA's assertion that the phone records of all Americans can be considered "relevant" to a terrorism investigation under the statute. She was followed by other supporters, sounding off one-by-one in a series of rapid-fire 30-second statements. "The NSA's interpretation is that all data is relevant all the time," said Rep. Joe Barton (R-TX). "That is simply wrong."

NSA defenders responded by echoing the White House and intelligence community's claims that the metadata program is an indispensable tool that saves American lives. "You may have heard the expression that in order to find the needle in a haystack, we first need the haystack. This takes a leaf blower and blows away the entire haystack," said Rep. Joe Cotton (R-AR), dismissively describing the metadata as "an excel spreadsheet with five columns." But Rep. Jim Sensenbrenner, who authored the original Patriot Act, clarified that the amendment wouldn't eliminate the agency's power to collect phone records under Section 215 — it would only limit its scope to "people suspected of involvement in a terrorist plot."

While Amash's blitz failed, the surprisingly close vote suggests there's strong support for future legislation curtailing NSA surveillance. The effort managed to generate some unconventional alliances, pitting Libertarian Republicans and privacy-minded Democrats against members of their own party loyal to the intelligence community and the Obama administration.

"National security is of paramount importance, yet the NSA's dragnet collection of Americans' phone records violates innocent Americans' privacy rights and should not continue as its exists today," said Sen. Mark Udall (D-CO), a NSA critic and member of the Senate Select Intelligence Committee, after the vote. "I am urging the president and the NSA to join this growing bipartisan coalition and work with Congress to focus the NSA's surveillance efforts on terrorists and spies — not innocent Americans."