What happens to cross-border supply chains that run through Texas?

They keep running, because the whole point of independence is to keep trade free and open, and a supply chain is just trade in motion. The goods, the trucks, the rail, the pipelines, and the ports do not move when the flag changes. What protects them is the same thing that protects all the rest: keeping the border low-friction by agreement.

A supply chain is sensitive to one thing, and Texas controls it

Supply chains do not care which government signs the treaty. They care about friction: delays at the crossing, paperwork at customs, tariffs at the line. That is the entire variable. The frightening forecasts about separation come from erecting trade barriers, not from independence itself. Britain's own budget watchdog found the long-run cost of Brexit, near 4 percent of GDP, "largely reflects" the non-tariff barriers Britain put up, not the act of leaving. Texas holds that variable nearly constant by keeping free trade with the United States and the dollar in circulation through the transition. Hold the friction down and the supply chain runs the way it does today.

The physical network is Texan and immovable

Look at what a supply chain actually is on the ground. It is the Port of Houston, the rail lines, the interstate highways, the pipelines, the warehouses, and the border crossings. Every piece of that is physically in Texas. Independence does not relocate a port or pick up a pipeline. The infrastructure that moves goods through Texas stays exactly where it is, owned and operated where it sits, which is why the goods keep moving.

Mexico is the proof that borders and supply chains coexist

The most integrated supply chains in North America already cross an international border every day. Components in automotive and electronics manufacturing routinely cross the U.S.-Mexico line multiple times during production, parts assembled on one side, integrated on the other, shipped back as finished goods. That is a supply chain that already spans two sovereign countries, two currencies, and two governments, and it is among the most efficient in the world. If a supply chain can run across the U.S.-Mexico border, it can run across a Texas-U.S. border, because the tool that makes it work, a trade agreement that keeps the crossing cheap and fast, is exactly the tool Texas would use.

Continuity is the negotiated default

After a vote, the relationship between Texas and the United States is settled through a transition in which existing arrangements continue while the details are worked out. Supply chains run straight through that transition. Both governments have every incentive to keep goods flowing, because walling off the line would damage businesses and consumers on both sides for no gain. The natural outcome, a free-trade arrangement that Washington wants too, locks the crossing open rather than closing it.

The bottom line

Cross-border supply chains running through Texas keep running, because the network is physically Texan, the only real risk is trade friction, and Texas is positioned to keep that friction low. The U.S.-Mexico border already proves that the most demanding supply chains on the continent work fine across an international line.