We should look at their education as a matter of national security.

And the people who were working on it have been told it's a matter of national security.

Tell him that it is now a matter of national security.

This is now a security matter, so he can deal with it.

The men from 1600 were the best in matters of security.

And so energy supply is a matter of national security.

"You can't answer the question because it's a matter of national security?"

As such, this becomes a matter of security, and is therefore not open to question.

This is a matter of national security, and I need some answers right now!

This is a matter of national security and subject to a police investigation.