Can policies be altered by events?

I have an event named Court Strikes Down Police Methods, triggered by angry Liberals and Jury Trials. It increases the number of Liberals and decreases the number of Patriots, to discourage the player from using oppressive Law & Order policies.

Ideally, I would like the policy to decrease the intensity some oppressive policy, such as Detention Without Trial. Can this be done by a scripted event?

Possibly, a high national debt could trigger an event that makes mandatory cuts in welfare, transport and public service spending.