“This will never happen again.” That’s what Bill Chapman, General Motors’ chief House lobbyist, said to me one day in 1975.

Mr. Chapman was referring to the wave of consumer and investor protection legislation that had been pushed through Congress during the preceding four years. He had been sent to build up the General Motors Washington team, which — along with other major companies in industries such as tobacco, energy and finance — had been taking a legislative beating.

At the time, I was chief counsel of the Commerce and Finance (and later the Oversight and Investigations) subcommittees chaired by Congressman John Moss, the California Democrat who was a leader in the consumer and investor legislative victories of those years.

As we stood in the hallway of the Longworth House office building those many years ago, I thought Mr. Chapman and his prediction (which was surely GM’s also) was crazy. It had been nine years since passage of the landmark National Motor Vehicle and Traffic Safety law, three years since President Richard Nixon had signed the Motor Vehicle Information and Cost Savings Act (known as the “bumper” bill), and two years since Mr. Moss and his allies rammed through the Consumer Product Safety Act. They had also secured enactment of a major securities markets reform bill (forcing competitive commission rates) and a sweeping law giving the Federal Trade Commission the authority to bring class actions to recover millions on behalf of defrauded consumers.

So I just smiled at Mr. Chapman’s prediction and walked away. But as it turned out, Mr. Chapman was absolutely right.

Among the major reasons why the prediction was and remains on target is that a few years later Congress began to slash its own expert staff — a staff that Mr. Moss and other legislators relied upon to research and investigate industry claims and to successfully move legislation forward.

For example, in 1976 Congress was being urged to deregulate the price of natural gas. The industry claimed that the nation was “running out of natural gas reserves” used to heat, cool and fuel much of the nation. There was a nationwide gas shortage; schools were closing in some states. The producers argued that only prompt deregulation of prices then controlled by the government could save the country from more shortages.

But Mr. Moss was skeptical and wanted objective data on whether the nation’s gas reservoirs were really running dry. He recruited a team of investigators and experts, and they flew by helicopter into the Gulf of Mexico and to other non-producing gas fields. They found many gas wells were intentionally shut down, not for any geological reason but because the industry wanted to force higher prices. They also found that the Federal Power Commission, which had authority to compel more production, was not doing its job.

Because of the information obtained from Mr. Moss’ investigation, Congress voted to keep price controls on existing natural gas, saving consumers billions of dollars in succeeding decades.

Then, under the leadership of then-House Speaker Newt Gingrich, the staffs of the main legislative expert agencies supporting Congress were sharply cut. Today they are less than one third the size of what they were before 1990, according to a 2017 report by the Brookings Institution. More than one of every three staffers is gone from the Congressional Research Service (CRS), the Government Accountability Office (GAO) and Congressional Budget Office. Also defunded was the new Office of Technology Assessment, which focused on developing technologies.

Of course, there were many reasons Congress reduced its own brain power and the wave of consumer and market-regulating legislation slowed to a crawl. They include a huge increase in funds expended by regulated industries to lobby congress. That spending went from $200 million in 1983 to $3.2 billion in 2015, as reported by the public interest group Public Citizen. There was also a decline in public confidence in government to remedy national problems.

But the results of the actions of Congress in the productive years of the 1970s saved thousands of lives, billions of dollars in injury costs, promoted competition and widely assisted American investors and consumers. Those laws have never been repealed, although some have been underfunded and undermined.

Without restoring its expertise, how can Congress deal effectively with issues like self-driving vehicles, internet privacy and foreign intervention in our elections?

House Speaker Nancy Pelosi has pledged to establish a Select Committee on Modernizing Congress, so that the legislative branch can have the capability to do its job. Absent that kind of tough action, Congress will continue to rely excessively on special interests and paid lobbyists for its brains. That is not a happy thought for the American people.

Michael Lemov (lemovlaw@gmail.com ) is an attorney who served as chief counsel to subcommittees of the House Commerce Committee, chaired by Congressman John E. Moss. He is the author of “Peoples Warrior, John Moss and the Fight for Freedom of Information and Consumer Rights” and “Car Safety Wars, 100 Years of Technology, Politics and Death.”