NEW ORLEANS (AP) — The future of a barrier of giant buoys that Texas Gov. Greg Abbot placed in the Rio Grande last year to deter migrant traffic may turn on whether a rocky, shallow stretch of the border river can be considered “navigable” and whether immigration sometimes constitutes a hostile invasion.

The full 17-member 5th U.S. Circuit Court of Appeals heard arguments on the issues in New Orleans on Wednesday, the latest courtroom debate in multiple legal disputes over border control between Democratic President Joe Biden and the Republican governor. The judges did not indicate when they would rule.

Part of the hearing touched on Texas’ claim that the barrier is authorized constitutionally as a means of defending against an invasion.

“Are you saying that federal law overcomes the constitutional right of the state?” Judge Edith Jones asked Justice Department attorney Michael Gray. She later added: “Under what circumstances can the United States thwart that attempt at self-defense?”