упорствовать в безнадёжном деле(The government during several administrations, and despite substantial opposition, persisted in Viet Nam in a hopeless undertaking. VLZ_58)
упорствовать в своём невежестве(напр., "It is not enough to be well-intentioned; one must strive to put those intentions into action in a capable way. One must consider the effect his actions will have on others. Looked at like this, to persist in ignorance is itself dishonorable. –Andrew Cohen" Aiduza)
