Among the documents declassified by Director of National Intelligence James Clapper on Wednesday was a letter from the office to members of Congress dated December 14, 2009. The letter is explicit in describing the collection of phone metadata, which became broad public knowledge following the Edward Snowden leaks in June. So why has Congress only become outraged this month?

Here's the relevant section, from the fifth page of the document.

The orders generally require production of the business records (as described above) relating to substantially all of the telephone calls handled by the companies, including both calls made between the United States and a foreign country and calls made entirely within the United States.

Precisely what the Snowden leaks revealed. That document was provided to members of Congress (and certain staff) in a secure location for a short period of time at some point after it was drafted. The same allowance was made for a similar letter in 2011.

Why, then, is it only now that members of Congress are calling for changes to that process? Clearly it's not a coincidence.

They knew but didn't understand the significance. One possibility is that the paragraph only stands out to us now because we know what we're looking for. The document is dense and lengthy, including further classified details about how and why the NSA conducts its surveillance. The section that follows the one above outlines the oversight procedures in place, including from Congress:

These programs have been briefed to the Intelligence and Judiciary Committees, to include hearings, briefings, and, with respect to the Intelligence Committees, visits to NSA. In addition, the Intelligence Committees have been fully briefed on the compliance issues.

And then, since the point of the letter was to sell Congress on extending the authorization, it then makes the case for the value of the programs. The letter is a bad-news sandwich, starting with mentions of 9/11 and ending with the "vital capability" the program provides. It is possible that members of Congress didn't understand what they were looking at.

They should have known, but didn't. It is also possible that they didn't look at it, or didn't look closely. National security reporter Julian Sanchez made that point on Twitter this morning.

That effort included going to read the document — during which time they were not allowed to photocopy or take notes on what they read. The NSA's argument in the letter that it briefed the proper subcommittees almost certainly held some similar restrictions. It's more recent argument that members of Congress have been briefed glosses over the fact that — for perhaps obvious reasons — the NSA constrained such briefings as much as possible.

If a member of Congress never saw the letters from 2009 and 2011, he or she certainly wasn't aware of the program.

They knew but couldn't do anything. Which brings us to the most likely rationale. Our representative democracy relies on the idea of informed consent, that a public who is aware of the subtleties between policy options and elects representatives based their policy preferences. This, you will note, is the ideal. In reality, we are often spurred to political action in sudden bursts.

For example, when classified information about government surveillance becomes public.

There were elected officials — Senator Ron Wyden of Oregon, for example — who pushed for reform of the NSA's programs prior to the Snowden leaks. Most, however, didn't.

Wired notes one excuse made by a one of the members of the aforementioned committees.

Sen. Patrick Leahy (D-Vermont) and the chairman of the Judiciary Committee, conceded today that the dragnet was no secret among lawmakers. But he noted a sense of irony, that lawmakers couldn’t publicly discuss it.

“But of course you can’t talk about it,” he said.

What Leahy did do is vote against the programs' extensions. But without the public outcry — and without the ability to generate that outcry in concrete terms — there wasn't enough compelling his colleagues to offer similar opposition.

Which meant that the debate was won by those who fell into the fourth category: They knew, but weren't concerned. This is the other reason informed consent is important. Without the public knowing about the program, those like Senator Dianne Feinstein of California would never have had any reason to explain why they adamantly support it. And those who truly didn't understand the ramifications of the metadata collection now certainly do.

Photo: Senators Leahy and Feinstein in front of an NSA-provided map showing thwarted terror activity. (AP)