THE BILLIONS of dollars being spent on infrastructure across the nation provide an opportunity to plan for a better America, but politics-as-usual favors sprawl over city. This anti-urban bias of national policies must end.

Over the past 60 years, cities have been hit by a painful policy trifecta: subsidization of highways, subsidization of homeownership, and a school system that creates strong incentives for many parents to leave city borders. Nathaniel Baum-Snow, an economist at Brown University, has documented that each new federally-funded “highway passing through a central city reduces its population by about 18 percent.’’

Subsidizing transportation decreases the advantage of living close together in cities, which should make every urbanite worry about the Senate’s fondness for using highway spending to fight recession. The current Senate jobs bill calls for a more than $30 billion increase for transportation over the next two years.

It is a mistake to think that spending on trains balances the scales. Cities will always benefit far less than exurbs from transportation because dense areas already have good means of getting around, like walking. Urban advocates would do better to either reduce highway subsidies or to balance that spending with more funding for urban schools.

Political leaders have long championed homeownership, but subsidizing homeownership is also anti-urban. Sixty-two percent of Boston homes are rented; 78 percent of Wellesley homes are owner-occupied. Cities are defined by apartments, and more than 85 percent of homes in multi-unit structures are rented. Suburbs are known for their single-family detached houses, and more than 85 percent of such homes are owner-occupied. Subsidizing homeownership, through Fannie Mae , Freddie Mac and the home mortgage interest deduction, lures people out of cities.

For many suburbanites, schools loom larger than fast commutes or subsidized mortgages. America’s local school system creates large incentives for education-oriented parents to move to homogeneous enclaves outside of city limits. Cities would benefit if the school system moved leftward, toward a more uniform national system like France, or rightward toward state-level vouchers that break the link between where you live and where your children go to school. School reforms that enable city schools to work more like a private market can harness the urban edge in innovation and competition that works so well in other industries, like restaurants.

The forces of history have created a moment where the right leadership could make America less anti-urban. The housing crisis, a renewed interest in infrastructure, fear of global warming, and the education reform movement could help bring about fairer policies for cities.

The housing bust exposed the myth that Fannie Mae and Freddie Mac were costless and exposed the folly of encouraging people to bet everything on the vicissitudes of the housing market. It is time to lower the million-dollar limit on the home mortgage interest deduction and to gradually reduce federal support for mortgage lending.

Across the country, a flurry of experiments is building the knowledge needed to improve urban schools. Education Secretary Duncan is trying to harness “a perfect storm for reform’’ by leading a “race to the top.’’ Education is not just the “great equalizer,’’ it is the great nation and city builder. Our country’s cities depend on the reformers’ success.

The environmentalist movement is recognizing that cities are far more energy efficient than suburbs due to smaller housing units and less driving. Greens need to fight both against suburban highways and for more urban development.

In 2009, America’s five least dense states were awarded $1,100 per capita in federal recovery grants while the five densest states, including Massachusetts, got $561 per capita. President Obama can change the tilt toward low density. The most urban president since Teddy Roosevelt, Obama needs to fight for cities, not just as a matter of justice, but because cities, and the creativity that comes when humans connect and learn from each other in dense areas, are the best hope for the country.

Edward L. Glaeser, a professor of economics at Harvard University, is director of the Rappaport Institute for Greater Boston.

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