Over the past few weeks, a quiet legal crisis has been unfolding on the US-Mexico border. Texas has seized control of part of the border and claimed the right to prevent federal authorities from exercising jurisdiction there. After the US supreme court ruled that the federal government could tear down razor wire erected by Texas authorities, the state vowed to erect more – and Governor Greg Abbott claimed that because the federal government had failed to protect his state from an “invasion” of refugees, it has “broken the compact between the United States and the States” and lost the right to exercise authority over the border altogether.
To understand why this is so alarming, you need to see it in two historical contexts. The first is the notion of a “compact” between the states. This idea holds that the constitution is not the supreme law of the land but rather a mere agreement between independently sovereign states. Those states hence retain the right to decide when certain actions by the federal government break the compact – and to reclaim their independence accordingly.
This idea – sometimes known as “compact theory” – was key to the quasi-legal arguments deployed by the Confederate states in the 19th century to justify first secession, and then civil war. As well as being rejected by the framers of the constitution, it was also........