First, Congress writes the laws of the land. The US system of course has checks and balance, where the Supreme Court can rule something unconstitutional. This means that a law is nullified until Congress either rewrite part of the constitution if the support is there (the consitutition is not a holy text you know), or a new Congress has to wait for the oldest SCOTUS judges dies. E.g. the extreme rightwing tilt of the current court explains why the moderat McCain-Feingold law was struck down, and the last election shows why it is time for age to do its thing. Of course, the current president chose who the new judges will be, again a part of the check and balance.
Now to Snowden, he is clearly not a whistleblower. What he is doing is civil disobedience, in the spirit of e.g. MLK when the civil rights movement broke immoral laws. Because, so far it has not been shown that NSA is doing anything illegal. And it is infuriating to read and hear commentators and journalists that claim what NSA is doing is either illegal, surprising or has been kept hidden from public. What the hell did all these people think the "Patriot Act" was all about?!
What was illegal was the early wiretaps done by the Bush administration; the solution was to expand the Patriot Act. The people back then that protested the Patriot Act were willefied by the Bush administration ("either you are with us, or you are against us"), and got a collective shrug from the corporate media. I just got to shake my head at liberals that are surprised that president Obama will use all the legal tools available to him to keep the homeland secure (thats is part of the job description), or at the republican media like fox that were so eager to defend the Bush teams illegal wiretaps and expansion of the Patriot Act who could not understand back then that Congress should pass laws that are acceptable whatever party the president belongs.
And no, the current rightwing SCOTUS will not find the NSA activities unconstitutional.
So dont feel so smug because you at least are against the collection of meta-data that NSA is doing. Inform yourself and the voters around you, and take responsibility to elect people to congress that will not be pushed around by lobbyist or the latest non-story in the corporat media (only one senator was strong enough to vote against the Patriot Act - Feingold - and he did not get reelected which says a lot about the voters).
Congress is at the moment disfunctional, not least because of a republican party and republican voters that does not seem to believe in anything but Obama bad and to cut taxes for the rich. But this is not good for either of the major parties or for the country. What is needed is functioning opposition party to challenge the ruling party and to bring about an informed debate about how to make the country stronger. Because these are difficult questions: how to find the right balance between decreasing the risk for terrorist attacks while protecting the privacy of the population. Or how to have a transparent government that you can trust, while ensuring that the information that will harm national security is kept away from potential terrorists. There are no easy answers.
Maybe Obama is correct when he states that this is the right time to start such an informed discussions? But then we have to move beyond voters looking at politics as a game where your team is winning or loseing. The politicians you want is the ones with principles but also who will look for the best possible compromise. And we need move beyond a corporate media that just reports he-said/she-said. What is needed is a media that calls out stupid, is able to point out consequences of a law for the future, and who has the courage to pick up difficult topics (instead of scrambling when the NSA story broke in a UK newspaper).
Things can only improve if we move beyond slogans like "government bad, deficits bad" to e.g. discussions on the right level of use of private and extremely expensive contractors to do the important government work of tracking down organised crime and terrorism. And to have a debate where conservative and liberals can try to find good checks and balances on a government that has the responsibility to keep most people safe from bombs, while not forgetting the Bill of Rights.