Suddenly, I’m getting more enthusiastic about watching the Democratic convention.  The latest ad from the DNCC’s prime-time speaker compares America unfavorably to China, demands more government spending, and its title “Rebuild” reminds voters of her original “you didn’t build that” rant to entrepreneurs.  What could go wrong?

The New York Sun can’t quite believe that someone who wants Elizabeth Warren to win would have approved this ad for distribution:

The first problem is mathematical. U.S. gross domestic product is about $15 trillion a year. Increasing infrastructure “investment” to the 9% Chinese level that Ms. Warren cites would mean an additional $1 trillion a year in government spending. That’s an immense spending increase. To put it in context, the entire federal government spent about $3.6 trillion in 2011, on revenues of about $2.3 trillion.

Where would this money come from? Not tax increases, right? Ms. Warren has already reportedly promised nearly a trillion dollar tax increase, spread over ten years, by raising the estate tax, imposing the Buffett Rule, and letting the Bush tax cuts expire for those earning $250,000 a year or more. But that money, she has said, would go toward deficit reduction. If Ms. Warren really wants to spend $1 trillion a year more on infrastructure, she’d need to eliminate all national defense spending ($705 billion) or all Social Security spending ($730 billion) and then find another more than quarter trillion dollars. Or else she’d have to go on the biggest borrowing or taxing binge in American history.

Math, though, is hardly the only problem with emulating China’s approach to infrastructure spending. History is another. America and China are at different junctures in our development. America built a lot of bridges, tunnels, and highways in the 1950s and 1960s when China was stuck under Communism. A lot of China’s spending now isn’t going to outpace America but to catch up with things that we’ve had here for decades, like potable water and a population that is mostly non-rural.

Finally, not all of China’s infrastructure spending is worth emulating. The Chinese Communist treatment of those who stand in the way of their projects makes Robert Moses, the mastermind of so many of New York’s neighborhood-destroying highways, look like Mother Teresa. For example, the group International Rivers reports that 1.2 million people were displaced to construct the Three Gorges Dam. That $40 billion project also reportedly had devastating effects on the Chinese river dolphin, river sturgeon, and paddlefish.

China is able to spend so much on infrastructure because it’s an un-free country. It lacks the rule of law that lets American community groups wage legal and political battles against big government projects. Ms. Warren may protest that when she’s talking about “infrastructure” she mainly means maintaining existing roads and bridges, not building brand new projects that flatten urban neighborhoods or destroy scenic rivers. But that’s not what’s happening in China.

And that’s not all.  One of the favorite examples of Chinese infrastructure spending among progressives like Warren is their commitment to high-speed rail.  That has turned into a $271-billion disaster for China, however.  Their trains don’t even run on time for all that money; China had to slow them down because of all the defects in the system.  Let’s ask Warren’s potential constituents how well the Big Dig project turned out, both financially and operationally.

Or, let’s not.  I for one cannot wait for Warren to go on prime-time television just before Bill Clinton formally nominates Barack Obama to tell the nation that her aim is to make America more like China.