By NEAL F. LANE
Houston

MITT ROMNEY said in all three presidential debates that we need to expand the economy. But he left out a critical ingredient: investments in science and technology.

Scientific knowledge and new technologies are the building blocks for long-term economic growth — “the key to a 21st-century economy,” as President Obama said in the final debate.

So it is astonishing that Mr. Romney talks about economic growth while planning deep cuts in investment in science, technology and education. They are among the discretionary items for which spending could be cut 22 percent or more under the Republican budget plan, according to the Center on Budget and Policy Priorities.

According to the American Association for the Advancement of Science, the plan, which Mr. Romney has endorsed, could cut overall nondefense science, engineering, biomedical and technology research by a quarter over the next decade, and energy research by two-thirds.

Mr. Romney seems to have lost sight of the critical role of research investments not only in developing new medicines and cleaner energy sources but also in creating higher-skilled jobs.

The private sector can’t do it alone. We rely on companies to translate scientific discoveries into products. But federal investment in research and development, especially basic research, is critical to their success. Just look at Google, which was started by two graduate students working on a project supported by the National Science Foundation and today employs 54,000 people.

Richard K. Templeton, chief executive of Texas Instruments, put it this way in 2009: “Research conducted at universities and national labs underpins the new innovations that drive economic growth.”

President Bill Clinton, for whom I served as science adviser from 1998 to 2001, understood that. In those years, we balanced the federal budget and achieved strong growth, creating about two million jobs a year. A main reason was the longstanding bipartisan consensus on investing in science. With support from Congress, Mr. Clinton put research funding on a growth path, including a doubling over five years (completed under President George W. Bush) of the budget for the National Institutes of Health.

In 2010, the federal government invested about $26.6 billion in N.I.H. research; those investments led to $69 billion in economic activity and supported 485,000 jobs across the country, according to United for Medical Research, a nonpartisan group.

Moreover, the $3.8 billion taxpayers invested in the Human Genome Project between 1988 and 2003 helped create and drive $796 billion in economic activity by industries that now depend on the advances achieved in genetics, according to the Battelle Memorial Institute, a nonprofit group that supports research for the industry.

So science investments not only created jobs in new industries of the time, like the Internet and nanotechnology, but also the rising tax revenues that made budget surpluses possible.

American science has not been faring so well in recent budgets. President Obama has repeatedly requested steady increases for scientific research, aimed at putting the budgets of three key science agencies — the National Science Foundation, the Department of Energy’s Office of Science, and the National Institute of Standards and Technology — on a path to double, by 2016, the combined $10 billion they received in 2006. But a polarized Congress has not delivered at that rate, and the goal could be nullified if next year sees the beginning of draconian cuts.

Meanwhile, the frontiers of science continue to expand. President Obama is proposing that the United States boost its overall national research and development investments — including private enterprise and academia as well as government — to 3 percent of gross domestic product — a number that would still lag behind Israel, Sweden, Japan and South Korea, in that order.

In an increasingly complex world, that should be only a start. If our country is to remain strong and prosperous and a land of rewarding jobs, we need to understand this basic investment principle in America’s future: no science, no growth.

Neal F. Lane, a professor of physics and astronomy at Rice University, was director of the National Science Foundation and the chief science and technology adviser to President Bill Clinton.