Fifty years ago today, Washington witnessed a revolution. The Freedom of Information Act went into effect, establishing Americans' right to know.

FOIA was a breathtaking accomplishment, the end result of a 12-year effort by John Moss, a Democratic congressman from California. The bill established that any citizen -- anyone, not just officeholders or journalists or well-connected insiders -- could ask the government for information, and the government had to respond. Every citizen had a right to know what the government was up to.

The act was part of a massive power reversal in the flow of information between citizen and state. In the 1960s and 1970s, the right to know grew alongside the right to privacy, twin efforts to enlarge government transparency and personal privacy. They were a response to a government that jealously guarded its own secrets while rifling through the personal lives of millions of Americans (a state of affairs that should sound familiar to anyone who's followed the last 15 years of American politics).

In mid-century Washington, secrecy was the coin of the realm. That secrecy was fueled by two related developments in the early Cold War: a fear of spies, and a faith in government by experts. The first meant that information had to be locked down; the second removed any imperative to share it. After all, what would the average Joe make of sociological studies, complex economic equations and detailed scientific schema? When anyone came knocking, even journalists and members of Congress, White House officials and agency heads simply refused to open the door.

Enter Moss, a tenacious reformer who harassed Republicans and Democrats alike. His constant haranguing of executive agencies and the White House left him few friends in the Oval Office, the intelligence community or the broader federal bureaucracy. But it did win him his law. In 1966, President Lyndon Johnson begrudgingly signed the Freedom of Information Act. The statement Johnson issued when signing FOIA emphasized the government's need for secrecy far more than the citizen's right to know, but the bill became law all the same.

It took a few amendments to give FOIA real teeth, but by the 1970s it was unlocking all sorts of state secrets, including the revelation of J. Edgar Hoover's massive surveillance of politicians and private citizens during his half-century at the FBI.

At the same time, the courts began moving to restrict the government's right to know. Though the idea of a right to privacy was hardly new in the 1960s – Samuel Warren and Louis Brandeis penned their famous essay "The Right to Privacy" in 1890 – that decade witnessed a burgeoning privacy jurisprudence. From contraception to marriage to personal telephone calls, the government was restrained again and again from impinging on what the Supreme Court deemed the "reasonable expectation of privacy."

And none too soon. At both the state and national level, the government was regularly meddling in deeply personal realms. Jim Crow laws told Americans who they could marry, where they could eat and worship and dance. State governments outlawed contraceptives and sexual acts. And the intelligence community, spread out among the CIA, FBI and military, kept tabs on all sorts of personal activities, weaponizing them to exert control over private citizens.

As the right to know and the right to privacy grew, faith in government plummeted. It was a mix of cause and effect. FOIA sprung out of a frustration with government secrecy – Moss asked a federal agency for information and the agency refused, stunning the first-term congressman. But as a tool for revealing government misdeeds and malfeasances, FOIA also helped dismantle a broad public faith in Washington.

Over the course of the 1960s and 1970s, as Americans learned more and more about the broad surveillance efforts of the federal government, thanks to public hearings like the Church Committee, they demanded more and more protection of their personal privacy, while insisting the government be more open with its own secrets. And for a while, the winds blew in the direction of transparency.

No more. With the dawn of the war on terror, secrecy came back en vogue in the nation's capital. A sprawling security state rapidly amassed powers of surveillance while operating largely out of sight. The citizen's right to know was trumped by the state's need to conceal; the citizen's right to privacy was overrun by the state's need to know.