Whether they work on climate change, evolution, vaccine safety, or any of a host of other issues, scientists frequently face resistance from people offering “alternative facts.” How did we come to live in a world where so many people feel vaguely supported opinions are just as valid as evidence-based scientific research—where people can't tell the difference between opinion and fact?

Part of the answer involves the long-standing efforts of the tobacco industry to deny evidence about tobacco's harms and of the fossil-fuel industry to confound understanding about climate change. These campaigns have undermined confidence in the idea that large amounts of scientific evidence produce a more accurate view of the world than do a few dissenting thoughts.

But there's another source for these doubts: the attack of conservative politicians on the U.S. Social Security program, which gives financial security to senior citizens. Republicans in Congress have recently threatened drastic cuts to Social Security and even privatization. Their ostensible reason is the need to balance the federal budget. “The numbers can't work” without big cuts to Social Security, former Republican finance committee aide Chris Campbell has declared. In fact, Social Security isn't a drain on the federal budget; it pays for itself through a dedicated payroll tax.

Why do conservatives keep attacking a successful program that pays for itself? Because of its success. Social Security is “big government” that works. Its accomplishments refute the conservative refrain that federal programs are costly failures and that the government should just leave things to the free market.

Most federal programs that conservatives love to hate were implemented in response to the failures of free markets. In the late 19th century anticompetitive business practices strangled markets and replaced them with monopolies. In the early 20th century one in every 1,000 U.S. workers was killed on the job. In the 1930s millions of able-bodied Americans were thrown out of work and onto breadlines through no fault of their own.

It wasn't the private sector that fixed these problems. It was government, particularly the federal government. The Sherman Antitrust Act of 1890 was passed to protect competition. Workers' compensation laws ensured that people injured on the job would receive redress. Laws were passed to limit child labor, expand access to education and—during the Great Depression—rescue American capitalism from a state of near collapse. Unsupported “alternative facts” frequently surfaced in debates over these programs. They appeared in later arguments over Social Security, too.

From its first payouts in 1937 through 1974, Social Security ran in the black; there were never more than two years in a row when the program had to draw on its own trust fund. From 1975 to 1981, however, the program ran deficits, and demographics suggested that things would get worse. In the early 1980s the Reagan administration suggested cutting benefits to make the budget look more balanced—without raising taxes or cutting military spending. This idea emboldened antigovernment ideologues who wanted to eliminate Social Security altogether by giving it to the private sector.

Congressional Republicans passed the baton to a “blue ribbon” committee led by famed economist Alan Greenspan, a libertarian. He has made the case for some privatization by (falsely) claiming that the program was irretrievably broken. Social Security was not in fact broken. Rather, like any 50-year-old thing, it needed some maintenance, and with modest adjustments to benefits and small payroll tax increases, the system was soon back on track.

The antigovernment forces tried again in the mid-2000s, aided by business interests. But polls showed that the more President George W. Bush talked about privatizing Social Security, the less the American people supported him, so he backed down.

Twenty years later we are in a similar place, but reasoned discussion is blocked by ideology that ignores evidence. This is the same fruitless dynamic that stalls action on the climate crisis. Senator Daniel Patrick Moynihan of New York popularized the adage that “everyone is entitled to his own opinion, but not his own facts.” Moynihan could have been talking about science, but he said this during a debate over Social Security.

This is an opinion and analysis article, and the views expressed by the author or authors are not necessarily those of Scientific American.