Spain is facing a serious security question after law enforcement sources reportedly identified individuals previously convicted of jihadism-related offenses among the migrants involved in last week’s mass incursion into Ceuta.

According to unnamed Spanish law enforcement sources cited Tuesday, people who had previously been expelled from Spain following jihadism convictions were detected within the large group that entered the Spanish enclave on the North African coast.

The report immediately raises an issue European governments cannot afford to treat as an afterthought: who is entering when borders are overwhelmed?

Ceuta has long been one of the most sensitive points on Europe’s external border. Large-scale attempts to cross into the Spanish territory can place enormous pressure on authorities responsible for identifying, screening and processing those who arrive.

The presence of people previously convicted in Spain on jihadism-related charges, if confirmed, would underscore the security risks that emerge when immigration enforcement and national-security screening are stretched by sudden mass movements.

This is not an argument against legitimate asylum claims or lawful immigration. It is an argument for something much more basic: governments must know who is entering their territory.

A criminal record involving jihadism is not a minor paperwork issue. Nor should European authorities assume that everyone arriving in a chaotic border surge can be treated as an indistinguishable mass.

For years, European leaders have been warned that weak border controls can create vulnerabilities that extend well beyond immigration policy. This report provides another reminder of why those warnings cannot simply be dismissed as political rhetoric.

The first responsibility of any government is protecting its people.

Borders are not abstract lines on a map. They are the front door to a nation—and national security starts with knowing who is coming through it.