(This post is from our new blog: Unofficial Sources.)

Senate Majority Leader Mitch McConnell announced on Tuesday that he will allow the Senate to vote on the USA Freedom Act, the surveillance reform bill that the House overwhelmingly passed last week, but that he had threatened to block. Congress only had a few days left to act before some key provisions of the Patriot Act expired, including the one the NSA has said gives it the authority to collect in bulk the phone records of Americans.

The bill would end that bulk collection, forcing the NSA to make specific requests to the phone companies instead. The bill also requires more disclosure — and a public advocate — for the secretive Foreign Intelligence Surveillance Court, while otherwise extending the three provisions that were due to sunset on June 1.

On the one hand, the bill would impose restrictions on the National Security Agency for the first time since the 1970s. On the other hand, in the context of the incredibly broad mass surveillance here and around the globe exposed by Snowden, the change would be minimal. It would do nothing to limit NSA programs officially targeted at foreigners that “incidentally” collect vast amounts of American communications. It would not limit the agency’s mass surveillance of non-American communications at all.

McConnell’s move would appear to set up one last showdown in what had, by some reckonings, been a great Congressional drama.

McConnell had called for a straight extension of the expiring provisions, for five years – or two months, if that was the best he could do. But the two most outspoken civil libertarians in the chamber –Sens. Rand Paul, R-Ky., and Ron Wyden, D-Ore. — had threatened a genuine “Mr. Smith Goes to Washington”-type filibuster if he tried any such thing.

So one could look at it like a big showdown that ended — or nearly ended — when McConnell caved.

But by another reckoning, this has all been theater — or maybe a puppet show, with the NSA as the puppeteers — and McConnell’s move was the inevitable, scripted denouement.

After all, when the extraordinary revelations of mass surveillance provided by NSA whistleblower Edward Snowden first emerged, the media and the public were horrified, and there was a clear expectation that Congress, suddenly informed, would do something about it.

But it didn’t. In part, the GOP’s sand-in-the-gears strategy has prevented Congress from doing much of anything at all. And in part, reformers underestimated how terrified politicians are of appearing weak when it comes to protecting the American people against the supposed dire immediate threat of attack.

Consider the sequence of events:

In one of the few surprises of the 113th Congress, a Snowden-inspired surveillance reform bill with actual teeth — championed by the political odd couple of Rep. Justin Amash (R-Mich.), and Rep. John Conyers (D-Mich.) — came within six votes of victory in the House in July 2013, killed only by desperate appeals from the White House and ruthless whipping from Republican leadership.

The next shot didn’t come until nearly a year later. An initial version of the USA Freedom bill was strongly supported by reformers — but Republican leaders, under pressure from the White House and the intelligence community, gutted its key provisions and actually granted the NSA expanded abilities. The bill passed in the House, but never even made it to the Senate, where a separate attempt also failed.

It was a heads-I-win-tails-you-lose scenario for the NSA — and it came up heads.

This time, there’s been one major difference: Congress actually has to affirmatively vote for something, or some authorities the NSA wants to keep will go away. That’s the only scenario the NSA wants to avoid.

Passing the Freedom Act would hardly be a defeat. As the New York Times wrote in a second-day story after the House vote — headlined “Why the N.S.A. Isn’t Howling Over Restrictions” — the key “reform” in the bill was actually proposed by the then-NSA director Keith Alexander.

So why was McConnell fighting so hard to extend the Patriot Act as is?

Maybe because if the hardliners gave up without a fight, it wouldn’t look like the reformers had prevailed.

So when the Freedom Act passes, after a ferocious fight at the buzzer, it will look like the reformers have won, when in fact it’s tails, they lose.

Photo: Chip Somodevilla/Getty Images