Schengen is the system Europe boasts about most. Free movement, no borders, no stamps, no queuing. And now two member states, Italy and Spain, are arguing over a video link because one of them imposed checks on the other.

Spanish interior minister Fernando Grande-Marlaska is demanding that Italy immediately lift the checks on passengers arriving from Spain. The measure, he says, makes no sense - entering Ceuta does not automatically mean entering the Schengen area. At the emergency video conference of interior ministers he repeated the point: Schengen was never at risk, and Rome's move is „completely unnecessary and disproportionate”.

A measure that is easy to introduce and hard to withdraw

Italian minister Antonio Tajani defends the checks as „prudent organisational measures” for national security. He expresses solidarity with Spain - and in the same breath insists the protection stays. A familiar formula: understanding in the sentence, a border check in practice.

Grande-Marlaska points to Frontex, which confirmed that border security was not compromised at any moment. So the agency whose job this precisely is says there is no problem, and the checks stand anyway. That is the difference between a security assessment and a political message - and the second usually lasts longer.

Brussels will „assess”

European commissioner for home affairs Magnus Brunner announced the Commission will evaluate whether suspending Schengen rules towards Spain was proportionate. At the same time he criticised the Spanish regularisation programme, under which more than 600,000 people without documents obtained residence permits.

So the Commission has objections to both sides, it will assess, and it will reach a conclusion at some point. In the meantime the barrier on the road is down.

Why this interests us from here

Because everyone from the Balkans who has waited for a visa, who has filled a folder with documents, who has explained at a counter why they were travelling - has heard the exact argument Spain is now using in its own defence. That they pose no risk. That the check is unnecessary. And they know how much that argument weighs when the state on the other side has already decided.

The difference is that Spain is a full member, with Frontex on its side and the Commission taking up its case. And the checks stand regardless. Would anyone react faster if it happened here?

Schengen is not a law of nature - it is an agreement between states that consent to trust each other. This week two of them showed how quickly that consent is withdrawn when politics at home starts to press. Those still waiting to get into that space are watching closely how the ones already inside behave.