Which preposition to use with belaboured

in Occurrences 1%

The last has been unmercifully belaboured in debate, the Prime Minister himself describing it as "a halting, lopsided, temporary makeshift."

with Occurrences 1%

In stern and solemn silence our force was marshalled for the attack, and then, without any word of warning, each one began belabouring with all his might the recumbent figures of the foe.

Which preposition to use with  belaboured