The opposite of populist nationalism is not globalist elitism; it is economic realism. And in the end, countries such as Britain, the United States, and now Italy will learn the hard way that reality always eventually wins.

Contrary to the warnings of some political analysts, even after the recent debacle in Canada, the G7 can and will play a role – albeit a less important one – on the global stage. But that does not mean that the summit's failure was cost-free.

Across the eurozone, political leaders are entering a state of paralysis: citizens want to remain in the EU, but they also want an end to austerity and the return of prosperity. So long as Germany tells them they can’t have both, there can be only one outcome: more pain, more suffering, more unemployment, and even slower growth.

It is not hard to imagine that if Italy's new government proceeds with its ambitious fiscal plans, instituting both a flat tax and a universal basic income, it could blow up the budget deficit. In that case, Italy could quickly find itself out of the eurozone and ring-fenced by capital controls, whether the government intended this or not.

Unlike many other European countries, Italy still has not restored economic growth to its pre-crisis level – a fundamental failing that lies at the heart of many of its political problems. Now that a new anti-establishment government is taking power, it remains to be seen if the economy will be remade, or broken further.

Economists who assure us that advanced-economy debt is completely “safe” sound eerily like those who touted the “Great Moderation” – the supposedly permanent reduction in cyclical volatility – a generation ago. In many cases, they are the same people.

Financial markets have finally woken up to the fact that Italy could soon be ruled by a populist government with designs to take the country out of the eurozone. And, given Italy's tepid economic performance since adopting the single currency a generation ago, there is little reason to think that the current crisis is a one-off event.

Severe political uncertainty, chronic slow growth, and a sovereign-debt level currently hovering around 160% of GDP already is enough for Italy to trigger a debt crisis. And there is no plausible resolution that would not generate additional risks and complications.

The federal government’s debt has risen from less than 40% of GDP a decade ago to 78% now, and the Congressional Budget Office predicts that the ratio will rise to 96% in 2028. While many blame the tax cuts enacted last year, the real reason lies elsewhere.

The May 19 deal between the US and China seems to have reduced tensions between the two countries. But, given the global nature of America's trade deficit, any effort to impose a solution focusing on one country will likely backfire.