JULIAN ZELIZER: When the Senate first met, there was an assumption that they would be a closed body and that they would meet in secret. And we've had a battle really since the founding through today of the tradeoff between that secrecy that some people think is required for good governing and transparency and accountability which many people think is equally important for our democracy to work.

MCEVERS: Were people OK with the Senate being a closed body, though, in a certain way over periods of time?

ZELIZER: Well, we don't really have great - we have no popular opinion polls until the 1930s and '40s. And in the period we do have those - the 1950s and '60s, which is really the high point I think of a lot of this secrecy in the middle of the Cold War and when the committees in both the Senate and House were very strong and deliberated on their own - there wasn't a huge outcry against it. People certainly registered pretty high levels of trust in Congress certainly by the late '60s and early '70s.

MCEVERS: Could you give us an example of a major piece of legislation that was drafted during this time in secrecy without any public debate?

ZELIZER: Well, the Medicare legislation was passed in 1965. It's the first major health care program that we have. The heart of legislation was worked out in the House in the ways and means committee where the chairman, Wilbur Mills, a Democrat from Arkansas, basically took an administration proposal that had been the subject of hearings, took it behind closed doors and totally transformed the bill, turning it into what we have today. And even Lyndon Johnson didn't know exactly what was going on until one of his staffers who was in the room reported to him what the House had actually done to it. And the bill is considered really watershed legislation.

MCEVERS: And then what changed? I mean I would assume it was Watergate that brought more transparency to Congress.

ZELIZER: Yeah, I mean it starts a little earlier. It starts in 1966. That's when Congress passes the Freedom of Information Act, and that's already a sign that there's members of Congress who believe that openness is a virtue and that transparency is a virtue and that citizens need to know what's going on in Congress. And then it wasn't until Vietnam and Watergate that you have this big push by reformers in Congress and outside of Congress to open up the system. And by the early '80s, there is an expectation that only in certain circumstances should Congress govern this way. Otherwise we should know what's going on.