Editorial writer and columnist

All right-thinking people agree: America’s infrastructure is in bad shape. The only debate is over how bad. Is our infrastructure “increasingly third-world” — per Slate’s Jacob Weisberg — or a “national disgrace” and “global embarrassment” — as Barry Ritholtz suggested in a recent column for The Post?

Data seem to support this gloomy conventional wisdom. In the World Economic Forum’s (WEF) latest Global Competitiveness Report, the United States’ infrastructure ranked 23rd, behind that of Malaysia and Barbados. Barbados!

The American Society of Civil Engineers gives America’s system a “D,” as President Obama often notes in support of his jobs bill, which provides $50 billion for transportation infrastructure and $10 billion to capi­tal­ize a national infrastructure bank.

So how come my family and I traveled thousands of miles on both the east and west coasts last summer without actually seeing any crumbling roads or airports? On the whole, the highways and byways were clean, safe and did not remind me of the Third World countries in which I have lived or worked. Should I believe the pundits or my own eyes?

For all its shortcomings, U.S. infrastructure is still among the most advanced in the world — if not the most advanced. I base this not on selective personal experience but on the same data alarmists cite.

The contiguous United States (that is, excluding Alaska and Hawaii) cover 3.1 million square miles, including deserts, mountain ranges, rivers and two oceanic coastlines. In a world of vast dictatorships (China), tiny democracies (Switzerland) and everything in between, from Malta to Mexico, the challenge of building and maintaining first-rate roads, bridges, railroads, airports and seaports in a country like the United States is extraordinary — and so is the degree to which the United States succeeds.

When you compare America’s WEF rankings with those of the 19 other largest countries, it stands second only to Canada, which is lightly populated — and whose infrastructure is linked with ours.

Among the 20 most populous countries, the United States ranks behind France, Germany and Japan, in that order. This would seem to confirm the case for U.S. inferiority in the developed world.

But France and Germany, in addition to being substantially smaller than the United States, are part of the European Union, a borderless single market from the Baltic Sea to the Black Sea. Sure enough, when you average out the scores of all 27 E.U. nations, the United States beats them by a clear margin.

The WEF produced its rankings based on a survey in which business executives were asked to rate their respective countries’ infrastructure on an ascending scale of 1 to 7.

Barbados’s 5.8 average score means that paradise’s execs are a smidgen happier with their infrastructure than are their American counterparts, who gave the United States an average score of 5.7. This is a “national disgrace”? Barbados has one commercial airport. The United States has more than 500.

The WEF asked executives to rate “railroad infrastructure,” without distinguishing between freight (which excels in the United States) and passenger (which does not).

Perhaps the survey’s subjectivity accounts for odd results such as Guatemala outranking Italy. Or that the U.S. score plunged below 6.0 for the first time in 2008 — proof of a sudden drop in the actual quality of our roads and bridges, or merely an indicator of the general despondency that hit U.S. businesses along with the Great Recession?

And while that D from the American Society of Civil Engineers is undoubtedly sincere, the organization has a vested interest in greater infrastructure spending, which means more work for engineers. The engineers’ lobby has given America’s infrastructure a D in every one of its report cards going back to 1998, except for 2001, when the mark was D-plus.

Top-notch though it is, the U.S. infrastructure could use an upgrade; by their very nature, roads, bridges and the rest require constant maintenance. The effort could boost both current employment and the economy’s capacity to grow in the future.

But it’s not just a matter of turning on the money tap and letting it flow. Though roads, rails and levees represent huge, upfront capital expenditures, the long-term benefits are often difficult to calculate objectively. The whole business is fraught with uncertainty, trade-offs and pork-barrel politics.

Nor are the economics of public works simple. After its economic bubble burst, Japan tried to restart growth with more than $6 trillion in infrastructure spending between 1991 and 2008. It ended up with little to show for it but a swollen national debt and lots of bridges to nowhere.

The United States probably needs more infrastructure spending. It also needs a serious debate about how much cash to invest and how to invest it. Alarmism promotes the former, not the latter.