That is, if the US wants to limit the downside of a recession.
Borrowing costs are low.
Private sector employees will become available.
Reducing non-value-added unemployment costs is sensible.
Infrastructure projects have limited terms and employees can be let go on the far side.
Useful infrastructure usually pays for itself over the long term (think Hoover Dam).
Employees are more likely to consume than people on unemployment, which addresses the demand side.
Will Trump do it?
Nope.