Imagine the coast-to-coast consternation if major defense contractors announced one by one that they would no longer build the next generation of fighter jets, tanks or missiles. Congressional hearings would be immediate and the consensus widespread on taking action to ensure a steady supply of these critical national-defense components.

The same level of alarm ought to be sounding — but unfortunately isn’t — about a real-world, rapidly dwindling manufacturing capacity that also undergirds national security. It’s the steady exit by large pharmaceutical companies from antibiotic research and development. A national strategy is urgently needed to keep the pipeline of new drugs flowing faster than infectious pathogens develop resistance.

Novartis became the latest drug-manufacturing giant to announce it is shutting down antibiotics and antiviral research programs. The Swiss-based firm will lay off 140 workers at its Emeryville, Calif., operations, according to a July 12 Bloomberg report. A spokeswoman said the move will allow the firm to “prioritize resources in other areas where we believe we are better positioned to develop innovative medicines.”

Novartis joins an exodus of other large drug companies: AstraZeneca, Allergan, Sanofi and The Medicines Company. Another, GlaxoSmithKline, “has put some antibiotics assets under review,’’ according to a July 14 story in the Business Times.

These high-level departures are disturbing. While smaller firms will continue to research new antibiotics, large companies are critical because they have the massive resources needed to finance the science and bring the new drugs to market.

Maintaining a steady flow of new drugs in development is vital because the bacteria that cause infectious diseases evolve to become less susceptible to treatments. A chilling example: There are strains of tuberculosis that are resistant to some or all of the known treatments for this disease. To have major players like Novartis drop out makes it significantly more difficult to stay a step ahead of these pathogens.

Minnesota infectious-disease expert Michael Osterholm has long warned of the perils of antibiotic resistance. His recent book, “Deadliest Enemy: Our War Against Killer Germs,” ought to be required reading for U.S. policymakers. In it, Osterholm provides an easy-to-understand explanation for why big companies are abandoning antibiotic research.

The market simply doesn’t provide a return on investment. New antibiotics need to be used sparingly to guard against resistance. But that translates to poor sales. There’s little incentive to invest monumental sums for that outcome. Companies understandably are steering resources to drugs that do sell well because they are taken over a lifetime (like cholesterol drugs) or used often to treat disease.

FDA Commissioner Scott Gottlieb merits praise for recently spotlighting this economic impediment and proposing different payment models. This merits more serious discussion and action by policymakers. Congress has created some incentives to spur antibiotic investment, but additional action is needed, as the Novartis exit underscores.

Osterholm rightly points out that solutions beyond economic research incentives are required. The overuse of antibiotics — physicians prescribing them unnecessarily — continues and must be reined in. More judicious use of antibiotics in agriculture must also be part of the solution.

Whatever it takes, the pipeline of new drugs must not be allowed to run dry. Said Osterholm: “Failure is not an option here.”