From President Trump’s Camp David retreat with cabinet officials and congressional leaders at the beginning of this year, word emerged that the president and his advisers are divided on the best policy for infrastructure. Gary Cohn, director of the National Economic Council, presented a detailed plan to make $200 billion in federal investments in order to unleash $1 trillion of total infrastructure investment through public–private partnerships, a plan that has now been leaked to the media. The president himself, meanwhile, reportedly prefers a more straightforward national building program.

Any discussion of infrastructure spending needs to recognize the stark reality of the …