Over the 40 years preceding Barack Obama’s first term in office, under Republican and Democratic presidents alike, the federal government claimed, on average, about 18 percent of the U.S. gross domestic product in taxes every year and spent slightly under 21 percent. This equilibrium was always going to be threatened by the retirement of the baby boomers. But the financial crash and the Great Recession upset it sooner than anyone expected.

As the economy cratered, so did tax revenue, dropping below 15 percent of GDP in 2009. Government spending, meanwhile, climbed to 25 percent of GDP, as the president’s stimulus bill tried to help fill the gap left by the private sector’s collapse.

This gulf between taxes and spending has closed, somewhat, in the three years since. But a new equilibrium will take many more years of growth and many more painful policy decisions to achieve.

The choice voters face will not determine exactly where this new equilibrium ends up. An Obama second term and a Mitt Romney first term would both feature a certain amount of can-kicking and a certain amount of compromise. A President Obama would probably accede to further spending cuts; a President Romney would likely accept the need for slightly higher tax revenue. Both men would continue to run large deficits as long as the recovery seemed weak.

But this year’s choice will make a difference. A vote for Obama is a vote for a future where spending stabilizes well above its 40-year average, and where tax revenue gradually rises – thanks to the leverage afforded by the expiration of the Bush tax cuts – to pay for Social Security, Medicare, the health care law and more.

A vote for Romney, on the other hand, is a vote for a future in which we at least try to make the fiscal adjustments necessary to keep taxing and spending at roughly the same rate as under Ronald Reagan, Bill Clinton and George W. Bush.

The conservative vision requires making structural changes to popular programs, and asking the middle class to accept further creative destruction in an age of insecurity. The last 50 years of Western European life, meanwhile, suggest that the higher-tax, higher-spending equilibrium favored by liberals can be comfortable.

But there’s a strong rebuttal to the case for accepting a bigger-government new normal. The European model of social democracy has its virtues, but it has always depended on the wealth created by American laissez-faire. As a recent economic paper points out, it’s easier for smaller countries to afford a more “cuddly” form of capitalism if big countries like the United States are driving global economic growth.

And it’s one thing for a young, fast-growing nation – like the United States of the 1960s – to embrace a permanently larger public sector. It’s quite another for a graying society with a stagnant economy and a sinking birthrate to do the same. There’s a risk of a vicious cycle, in which a shrinking working-age population bears the burden of growing old-age entitlements, which in turn discourages the risk-taking and family formation required to keep the system solvent. Already our government redistributes too much from the young to the old, from working families to retirees. To accede to this government’s permanent expansion is to walk into the kind of economic and demographic trap that has ensnared the weaker economies of Europe today.

Obama did not single-handedly put us on this path. But he has kept us on it, and campaigned for re-election as though taking it had no downsides. He’s the candidate of the Medicare status quo in a country facing an entitlement crunch, of government bailouts, and of contraceptive mandates in a society with a birth dearth.

For an incumbent president facing a mistrusted opposition party, this may prove a formula for a narrow victory. But for the country that might vote to re-elect him, it risks four more years of drift, stagnation and decline.