[URSpider94]

The US government not spending money looks like:

-- Hiring freezes, or even furloughs or layoffs -- Delays in capital projects (new buildings, bridges, airports)

This means less money in the pockets of employees, as well as less money to contractors, who have less money to pay their employees and suppliers, and so on. If people have less money, then they can't spend as much money, and thus the economy grows less fast, or stops growing.