Which preposition to use with impugn

before Occurrences 1%

Yet such has been the factious temper of the times that the correctness of this decision has been extensively impugned before the people, and the question has given rise to angry political conflicts throughout the country.

by Occurrences 1%

5. impugn by twenty-two arguments, Tritemius, Munster, Magdeburgenses, and many others relate for a truth.

in Occurrences 1%

Each party uses it or drops it to suit the vision it has faith in, but neither impugns in principle its general theoretic authority.

of Occurrences 1%

The identification has been impugned of late, but, as I think, without due reason.

Which preposition to use with  impugn