step in

[vil]

Dear teacher,

Would you help me to make the proper choice of a interpretation of the expression in bold in the following sentence?

Spanish airspace was reopened on Sunday after the military stepped in and forced the controllers to return to work - with the threat of jail if they refused the order.

step in = intrude or
step in = to help somebody in a disagreement or difficult situation

Thanks for your efforts.

Regards,

V.

[apex2000]

Neither. Simply moved in, literally.