Hatch, now 84, co-sponsored a number of bills with Democrats over the years, often with Sen. Ted Kennedy of Massachusetts. The two men were sometimes called “the odd couple,” for their politically mismatched friendship.

In 1997, the two proposed a broad new health safety net for kids — the Children's Health Insurance Program.

“This is an area the country has made enormous progress on, and it's something we should all feel proud of — and Senator Hatch should too,” said Joan Alker, executive director of Georgetown University's Center for Children and Families.

Before CHIP was enacted, the number of uninsured children in America was around 10 million. Today, it's under half that.

Hatch's influence on American health care partly came from the sheer number of bills he sponsored — more than any other living lawmaker — and because he was chairman of several powerful Senate committees.

“History was on his side because the Republicans were in charge,” said Dr. David Sundwall, an emeritus professor in public health at the University of Utah and Hatch's health director in the 1980s.

When Ronald Reagan was elected president in 1981, the Senate became Republican-controlled for the first time in decades. Hatch was appointed chairman of what is now known as the Health, Education, Labor and Pensions Committee. The powerful legislative group has oversight of the Food and Drug Administration, Centers for Disease Control and Prevention and the National Institutes of Health.

“He was virtually catapulted into this chairmanship role,” Sundwall said. “This is astonishing that he had chairmanship of an umbrella committee in his first term in the Senate.”

In 2011, Hatch was appointed to the influential Senate Finance Committee, where he later became chairman. There he helped oversee the national health programs Medicare, Medicaid and CHIP.

Hatch's growing influence in Congress did not go unnoticed by health care lobbyists. According to the watchdog organization Center for Responsive Politics, in the past 25 years of political campaign funding, Hatch ranks third of all members of Congress for contributions from the pharmaceutical and health sector. (That's behind Democratic senators who ran for higher office — President Barack Obama and presidential nominee Hillary Clinton).

“Clearly, he was PhRMA's man on the Hill,” said Dr. Jeremy Greene, referring to the trade group that represents pharmaceutical companies. Green is a professor of the history of medicine at Johns Hopkins University School of Medicine. Though Hatch did work to lower drug prices, Greene said, the senator's record was mixed on the regulation of drug companies.

For example, an important piece of Hatch's legislative legacy is the 1984 Hatch-Waxman Act, drafted with then-Rep. Henry Waxman, an influential Democrat from California. While the law promoted the development of cheaper, generic drugs, it also rewarded brand-name drug companies by extending their patents on valuable medicines.

The law did spur sales of cheaper generics, Greene said. But drugmakers soon learned how to exploit the law's weaknesses.

“The makers of brand-name drugs began to craft larger and larger webs of multiple patents around their drugs,” aiming to preserve their monopolies after the initial patent expired, Greene said.

Other brand-name drugmakers preserved their monopolies by paying makers of generics not to compete.

“These pay-for-delay deals effectively hinged on a part of the Hatch-Waxman Act,” Greene said.

Hatch also worked closely with the dietary supplement industry. The multibillion-dollar industry specializing in vitamins, minerals, herbs and other “natural” health products, is concentrated in his home state of Utah.

“There was really no place for these natural health products,” said Loren Israelsen, president of the United Natural Products Alliance and a Hatch staffer in the late 1970s.

As the industry grew, there was a debate over how to regulate it: Should it be more like food or like drugs? In 1994, Hatch sponsored the Dietary Supplement Health and Education Act, known as DSHEA, which treats supplements more like food.

“It was necessary to have someone who was a champion who would say, 'All right, if we need to change the law, what does it look like,' and 'Let's go,'” Israelsen said.

Some legislators and consumer advocacy groups wanted vitamins and other supplements to go through a tight approval process, akin to the testing the Food and Drug Administration requires of drugs. But DSHEA reined in the FDA, determining that supplements do not have to meet the same safety and efficacy standards as prescription drugs.

That legislative clamp on regulation has led to ongoing questions about whether dietary supplements actually work and concerns about how they interact with other medications patients may be taking.

DSHEA was co-sponsored by Democrat Tom Harkin, then a senator from Iowa.

While that kind of bipartisanship defined much of Hatch's career, it has been less evident in recent years. He was strongly opposed to the Affordable Care Act, and in 2018 called supporters of the heath law among the “stupidest, dumb-ass people” he had ever met. (Hatch later characterized the remark as “a poorly worded joke.”)

In his farewell speech on the Senate floor in December, Hatch lamented the polarization that has overtaken Congress.

“Gridlock is the new norm,” he said. “Like the humidity here, partisanship permeates everything we do.”

This story is part of a partnership that includes KUER, NPR and Kaiser Health News.

Read more: 

• Hatch, Wyden reintroduce RESA as omnibus battle looms
• Hatch pushes for Medicare split
• Hatch to Sebelius: 'Untruthful' on PPACA