Construction workers pour concrete as part of a bridge expansion project in California.

The rest of the planet bears a warning for President Trump's plan to lean heavily on private business in conjuring a trillion dollars' worth of American infrastructure: Handing profit-making companies responsibility for public works can produce trouble.

In India, politically connected firms have captured contracts on the strength of relationships with officialdom, yielding defective engineering at bloated prices. When Britain handed control to private companies to upgrade London's subway system more than a decade ago, the result was substandard, budget-busting work, prompting the government to step back in. Canada has suffered a string of excessive costs on public projects funneled through the private sector, like a landmark bridge in Vancouver and hospitals in Ontario.