A showdown is set to take place in the US House of Representatives today in what many hope will be a watershed moment for the fight against the National Security Agency's dragnet surveillance programs. After weeks of outrage from members of Congress and the public, a novel amendment to an annual defense appropriations bill is looking to smother what some consider the most pernicious aspect of the spying activities exposed by whistleblower Edward Snowden.

The amendment, led by Representative Justin Amash (R-MI), would stop the NSA's phone metadata program from collecting millions of Americans' communications records without suspicion of a crime. The proposal comes after a secret court order revealed that Verizon is being forced to turn over all its customers' calling records to the NSA on an "ongoing, daily basis," and the threat has become real enough that the federal government is now intervening in an attempt to stop the amendment from passing.

On Tuesday, NSA director Gen. Keith Alexander held a unexpected, four-hour confidential briefing, presumably to try and persuade lawmakers into rejecting the proposal when it comes to vote this week. On the House floor, Rep. Richard Nugent (R-FL), the sponsor of a different amendment to the defense bill, cautioned against Amash's proposal, saying that while he is angered by the NSA revelations, "to try and legislate these issues atop a [Department of Defense] appropriations bill isn't the right way to go about it."

The White House also issued a panicked statement, protesting that the amendment is "not the product of an informed, open or deliberative process" and urging instead for "an approach that appropriately takes into account the need for a reasoned review of what tools can best secure the nation."

But a lack of information and open dialogue is exactly what's been at the core of the controversy surrounding the NSA programs. Speaking yesterday at the Center for American Progress, Senator Ron Wyden (D-OR) said that the public was "actively misled" about the metadata program, warning that "the combination of increasingly advanced technology with a breakdown in the checks and balances that limit government action could lead us to a surveillance state that cannot be reversed."

"By allowing the executive to secretly follow a secret interpretation of the law under the supervision of a secret, non-adversarial court and occasional secret congressional hearings, how close are we to James Madison's 'very definition of tyranny?'" he said during the ominous speech.

Wyden and Senator Mark Udall (D-CO), both members of the Senate Select Intelligence Committee, have been warning for years that these secret FISA courts give the NSA broad surveillance authorities which go far beyond the scope of the law as written. Other members of Congress, who are not briefed to the same extent as the two senators, joined in loudly demanding that the program be reined in at a hearing of the House judiciary committee last week.

A new poll published today by The Washington Post says that 74 percent of Americans believe the metadata program has intruded on privacy rights. But of those polled, 57 percent still say they believe it's more important that the government be able to investigate terrorist threats.

Meanwhile, online activist groups like Demand Progress and Fight For The Future are encouraging Americans to call their representatives and voice support for Amash's amendment, which is among 100 other proposals expected to be voted on starting today. Even if passed, the amendment would still depend on the passage of the underlying defense appropriations bill, but Wyden said the fact that it has gotten this far is "another step, as i've outlined, in the march to a real debate" on NSA surveillance.