That advantage has entirely eroded over the past 30 years. It will take an active government to reverse this stagnation — from prenatal and early childhood education straight up through adult technical training and investments in scientific and other research. If government is “inconsequential” in this sphere, then continued American decline is inevitable.

Then there are the long-term structural problems plaguing the economy. There’s strong evidence to suggest that the rate of technological innovation has been slowing down. In addition, America is producing fewer business start-ups. Job creation was dismal even in the seven years before the recession, when taxes were low and Republicans ran the regulatory agencies. As economist Michael Spence has argued, nearly all of the job growth over the past 20 years has been in sectors where American workers don’t have to compete with workers overseas.

Meanwhile, middle-class wages have been stagnant for a generation. Inequality is rising, and society is stratifying. Americans are less likely to move in search of opportunity. Social mobility has been flat for decades, and American social mobility is no better than European social mobility.

Some of these problems are exacerbated by government regulations and could be eased if government pulled back. But most of them have nothing to do with government and are related to globalization, an aging society, cultural trends and the nature of technological change.

Republicans have done almost nothing to grapple with and address these deeper structural problems. Tackling them means shifting America’s economic model — tilting the playing field away from consumption toward production; away from entitlement spending and more toward investment in infrastructure, skills and technology; mitigating those forces that concentrate wealth and nurturing instead a broad-based opportunity society.

These shifts cannot be done by government alone, but they can’t be done without leadership from government. Just as the Washington and Lincoln administrations actively nurtured an industrial economy, so some future American administration will have to nurture a globalized producer society. Just as F.D.R. created a welfare model for the 20th century, some future administration will have to actively champion a sustainable welfare model for this one.

Finally, there is the problem of the social fabric. Segmented societies do not thrive, nor do ones, like ours, with diminishing social trust. Nanny-state government may have helped undermine personal responsibility and the social fabric, but that doesn’t mean the older habits and arrangements will magically regrow simply by reducing government’s role. For example, there has been a tragic rise in single parenthood, across all ethnic groups, but family structures won’t spontaneously regenerate without some serious activism, from both religious and community groups and government agencies.

In short, the current Republican policy of negativism — cut, cut cut — is not enough. To restore the vigorous virtues, the nanny state will have to be cut back, but the instigator state will have to be built up. That’s the only way to ward off national decline.