Tough measures should be taken against juvenile delinquents.

Literal

Delinquents [toward-に対して] hard-line measures [object-を] take [should-べきだ].

非行者 means 'delinquent.' 強硬な対策を講じる is a formal expression meaning 'to take tough measures.' ~に対して marks the target. ~べきだ expresses moral obligation.