For years, Seattle was the first place I looked when I thought about growing my company in the United States. I live in North Vancouver, B.C. Doing business with people a short drive away made sense.

Now we’re putting our growth elsewhere. Washington should pay attention to decisions like ours. The state can track the decline in traffic across the border . It will have a much harder time counting businesses that never arrive.

On Sept. 22, Caseway, the company I run, withdrew from a Canadian government technology accelerator in Silicon Valley . We had been selected from 137 applicants for one of eight places. The program charges no participation fee , though companies cover travel and accommodation. Giving up that opportunity was a difficult decision.

Consider what had happened over the past few months: In July, the United States declined to extend the United States-Mexico-Canada Agreement , although it remains in force. In August, it imposed 50% tariffs on certain Canadian goods . On Sept.…