This will be a useful lawsuit. I think that this will be a very different lawsuit from the one the ACLU is currently pursuing. First, it is being led by two US Senators from vastly different political perspectives, which gives it tremendous credibility with a wide base of people.

Additionally, if the USG falls back on the national security argument yet again, then this will damage the Obama administration's credibility even more, and that will be a useful outcome as well.

As an aside, it's funny how quickly Obama has gone from a novelty (first black president, exciting!) to just a very weak, unprincipled leader, and who weakens himself even more with every backroom deal with wall street, every promotion of Bush-era hawks, every prosecution of reporters under the Espionage Act, and every defense of mass surveillance of Americans. My sense is that he is under the full sway of his advisors and underlings, and he lacks the cajones to think for himself and stand up to them when they argue for practicality over principle. Clearly our political system needs to do a better job of selecting strong, intelligent, moral leaders, rather than just well-spoken ones. (An interesting problem in itself, and one which I think is only partly addressed by campaign finance reform.)

But the other lesson from this is that our system of checks and balances is not working. This suit is an attempt to use the judicial to check the executive. A laudable attempt to work within the system. But as you mention, the executive is not shy about playing their trump card - keeping secrets vital to national security - rendering a judicial check impossible. Meanwhile, Congress is still in very poor shape, with Tea Party morons so fixated on taxation that they ignore everything else. (Although I must admit, that in times like these "starve the beast" does seem mighty appealing. What the hell are we doing giving Obama $1T a year to play with, given his lack of judgement and scruples? Indeed, what man or woman exists that can be trusted with that kind of power, especially given the glaring weaknesses in our system of checks and balances?)

We've seen some egregious, shameless use of structural weaknesses in our system, hacks that previous generations of senators and presidents have been deeply reluctant to use - apparently well aware of the cost of using them. Executive use of "national security" to quash judicial check is one; indiscriminate and constant use of filibuster to intentionally stop congress from functioning at all, even on routine matters.

Fundamentally, political systems are designed to allow people with conflicting views to live in peace together, and to cooperate for mutual benefit. Without these systems, we devolve into tribes, mainly on ethnic and racial grounds, fighting for dominance over each other. We went from democracy at the city-state level, back to absolute monarchy, and now we're trying democracy at the national level.

But remember this is all new ground; the US is only 238 years old. In essence, the US is a startup, and it might fail, and it could fail catastrophically or just kind of fizzle out. (I hope doesn't, though, because I really love the idea of Star Fleet being HQ'd in San Francisco).