Catch one terrorist, a minor actor, and release him, and then say “We did our part. Now you release Shalit”. If they fail to do so, declare them in breach of the only deal they’ll ever get, find them and kill them.
Catch one member of hamas and kill him, and then say “We did our part. Now you release Shalit”. If they fail to do so, do it again and again until they do.