The industry’s own explanations — that other entities in America’s byzantine health care system are to blame for most price increases, and that its products are expensive and risky to make — are tough to swallow, given drug companies’ conspicuous profit margins. Its response to the crisis of soaring drug prices has been meager at best — and duplicitous at worst. Last year , several companies agreed to hold off on planned price increases, but only for six months, and only after President Trump chastised them on Twitter. Those same companies have aggressively resisted both state and federal efforts to enact formal changes to drug pricing rules.

Mr. Trump has not kept his campaign promise to “negotiate like crazy” with drug makers to lower the cost of their products, and his statement last May that the industry would soon announce “voluntary, massive” price cuts came to naught. But his bluster on the issue, along with his blueprint for resolving it, have at least helped to keep a spotlight on the pharmaceutical industry and its questionable practices.

If the members of the Senate Finance Committee want to make use of that spotlight, here’s what to ask executives on Tuesday:

How do you determine list prices for drugs? Who decides the factors that go into the companies’ drug-pricing formulas, and why can’t those formulas be made public? Senators should also ask Olivier Brandicourt, the chief executive of Sanofi — the only major insulin maker scheduled to participate in the hearing — why the cost of insulin continues to rise year after year, given that the drug has been available for roughly a century, and in many cases still enjoys patent protection. On Friday , Senator Chuck Grassley and now-Senator Wyden, the ranking members on the Finance Committee, opened an investigation into insulin prices.

What’s a fair profit margin for lifesaving products? A common lament among pharmaceutical executives has been that without enough profit from one drug, companies can’t afford to make the next one. That’s a fair point. Still, many leading companies enjoy billions of dollars a year in pure profit, even as lives are put at risk for want of basic medications. Insurers are subject to a 15 to 20 percent cap on profits and administrative expenses . Congress should consider a similar requirement for certain prescription drugs.

How much do you spend on research and development, and where do those dollars go? Pharmaceutical companies routinely argue that drug prices are high because research and development is expensive and because any successful drug is preceded by many failures. I ndustry critics , however, note that a good deal of basic research is funded by the federal government, through the National Institutes of Health , and not by the drug makers. Many leading drug makers spend most of their research dollars looking for new uses of existing drugs, not on risky innovations. And independent studies show that research and development costs for drug companies are not large enough to explain high drug prices.