President Barack Obama and the Federal Reserve rescued Americans from the 2007-08 financial crisis with aggressive fiscal policies and by pouring trillions of dollars in financial markets, and their efforts were greatly aided by several one-time events.

During the financial crisis, cars and trucks were not replaced and the economy emerged from the crisis with a lot of pent-up demand. Also, lower gas prices and better internal combustion technology, which permitted higher gas mileage, shifted demand toward SUVs and trucks, and greatly boosted sales and transactions prices for American-made vehicles.

The shale revolution gave a mighty jolt to U.S. oil and gas production and boosted demand for oil-field equipment.

The post-crisis write-off of credit-card debt and recovery of housing prices to pre-recession levels restored household balance sheets and for a time boosted consumer spending. Similarly, easier terms for student loans gave a jolt to spending among young people on tuition, room and board, and other paraphernalia associated with attending college.

Eight years later, however, the economy still remains challenged to accomplish much more than 2% growth, and policy makers must reckon with the fact that stimulative macroeconomic policies and one-time developments have run their course.

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On the demand side, most Americans now have well-stocked garages and cars last a lot longer. Millennials don’t share with Baby Boomers a love affair with automobiles, and Detroit will either have to slash transactions prices or make fewer vehicles.

With oil prices US:CLU7 stuck at around $50 a barrel or less, drilling activity will likely soon peak again soon.

The impulse to aggregate demand provided by debt forgiveness and higher housing values on consumer spending has run its course — while not declining, retail sales continue to disappoint even as the economy emerged from its usual winter chill.

The strong dollar BUXX, -0.19% (pick what reasons you like) and trade deficit and the improved-but-still-historically weak demand for new homes — in part, caused by the heavy burden imposed by student loans — are sapping demand from the manufacturing and construction sectors.

On the supply side, the steady stream of corporate taxes abroad has left the United States with one of the highest and least competitive business tax structures among industrialized countries.

The growth of entitlements and dysfunctions in education have left too many otherwise able-bodied adults without adequate skills to compete in post-industrial, globalized labor markets and disinclined to work — 7 million men between the ages of 25 and 54 neither hold a job nor are actively seeking employment.

Now if the Trump administration wants to preside over an economy that grows at even 25, it had better address the backlog of structural challenges — tax and entitlements reform, improving education, and reorienting immigration policy to those with skills the economy needs as opposed to the current emphasis on family reunification.

Republicans talked a better game out of power than they are willing to play with control of the White House and Congress.

Fixing trade means asking Americans to pay more for toasters at the Wal-Mart WMT, -1.02% in exchange for better jobs, which would raise aggregate living standards overall. Reforming and lowering taxes on business requires embracing border tax adjustments and making the corporate tax look like a value-added tax (the crux of the House plan).

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Health-care reform requires cleaning up Medicaid — ending access for those who refuse to work. Education reform requires cracking down on colleges that offer little value added and for-profit schools that sell bogus programs to unwitting poor and immigrant students.

All those issues have hit resistance or outright roadblocks either in the administration, among members of Congress or between GOP leaders in the two branches. While some legislation will be achieved, not enough may happen soon enough to keep the economy from driving off another cliff.