The word “transparency” has been much in vogue on Capitol Hill lately. The stimulus package contained unprecedented requirements for tracking where and how federal dollars are spent. Some members of Congress have openly been pushing the National Security Agency to account for its surveillance of U.S. citizens’ e-mails. President Obama’s plans for revamping financial regulation have brought renewed calls for greater openness on the part of the Federal Reserve, one of the most habitually opaque institutions in Washington.

These are refreshing developments. A big part of Congress’ role in our democracy is to ensure that the executive branch carries out its responsibilities to the American people in plain sight — or, at least, as openly as the demands of national security permit.

The presumption in a free society is that government will operate in the light of day, allowing its actions to be gauged and assessed, and its decision-makers to be held accountable to the American people. There are limits, of course, especially when it comes to national security, but secrecy is too often used as an excuse to cloak positions that politicians don’t want to reveal, or mistakes that bureaucrats would rather cover up, or simply to avoid accountability for actions that wouldn’t stand up to public scrutiny.

I don’t mean to suggest that transparency is always called for, but the institutions of our government function better when they do so visibly, rather than in the shadows.

This goes especially for Congress. On the whole, it has a better record of openness than the executive branch, but it’s “the people’s branch” — it ought to do better. Over the last few decades it has made some significant strides on this score: putting television cameras in the House and Senate chambers and in committee hearings; requiring recorded votes both on the floor and in committee; opening up conference committees; moving — at least in the House of Representatives — to make campaign filings more easily available, and requiring more information from lobbyists.

All of this makes legislators more accountable to the people who elect them and more accessible to the various stakeholders who will be affected by legislation.

Yet openness in Congress is a work in progress, not a done deal. Increasingly, for instance, important legislation is being put together by just a few leading members, sometimes without amendments or full-on debate being allowed. The drive to open conference committees has had the unforeseen side effect of making them less important — the leadership of both houses often cooperates, now, to sidestep them so that deals can be struck in private.

While the 110th Congress took the important step of making individual members’ responsibility for particular earmarks more transparent, it is still too hard to find out whether officers of companies benefiting from those earmarks made campaign contributions to the members who sponsored them.

And although Congress has tried to strengthen the disclosures required of lobbyists, it has been less assertive about enforcing them — according to a recent report by the U.S. Government Accountability Office, a sample group of lobbyists failed to document fully their activities in more than half the disclosure reports they filed, as required by law.

While secrecy breeds problems for government as a whole, I believe it is especially problematic for Congress. It makes ordinary Americans more cynical, limits the access of stakeholders, and permits members to avoid accountability for their actions and cut corners they shouldn’t cut. In other words, it creates both political problems for Congress — as measured by lack of trust in the institution — and makes legislation less responsive than it would be if it were openly created and debated.

As a member of Congress, I often encountered a troubling lack of confidence in the American people on the part of both executive-branch officials and my congressional colleagues. They believed that it was fine for them to know things that most Americans didn’t. If I’ve heard it once, I’ve heard it a thousand times: “Trust me; I know.” This is fine for troop movements, but in most cases I believe they underestimated the sophistication and good judgment of the American people. “Let the people know the facts, and the country will be safe,” Abraham Lincoln once said.

And while I thoroughly agree with him, I would add one point: If it is the responsibility of Congress and the White House to hold themselves to high standards of transparency, it is equally the responsibility of voters and media to demand openness and accountability of their government.

Lee Hamilton is director of the Center on Congress at Indiana University. He was a member of the U.S. House of Representatives for 34 years.