The mechanism. Everyone covers Vulcan Materials VMC as an infrastructure-bill beneficiary — more federal highway obligations, more asphalt, more crushed stone. That's real but secondary. The bigger swing factor is quieter: aggregates (crushed stone, sand, gravel) are too heavy and low-value-per-ton to ship far, so every market is effectively local — a quarry 30 miles away might as well not exist. That makes two non-spending policy levers decisive: (1) DOJ/FTC merger review, which determines how much further the industry can consolidate before regulators force divestitures, and (2) municipal zoning and permitting, which can take a decade or more and functions as a near-total barrier to new supply. DOJ's own enforcement record proves the point — it required Vulcan to divest 17 aggregate facilities to clear its Aggregates USA acquisition, and forced divestitures again in the CalPortland-Vulcan California ready-mix deal after California's AG flagged San Diego concentration. Antitrust isn't a tail risk here; it's the mechanism setting the ceiling on how consolidated — and pricing-powerful — the industry gets.