Isn't talking with others to develop a shared interpretation of a decision one way to influence it? And that would be part of monitoring the whole decision-making process, right?
You go to meetings, you talk about what happened with the decision-makers, you share others' interpretations, introduce them to the decision-makers, if possible, and share your interpretation with other d-m's in other locales, and, last but certainly NOT least, the general public!
So, the editorial, the letter to the editor, blogs, e-mails, and plain old socializing, should all work as forums for spreading an interpretation.
And, if the interpretation is everywhere, and established (e.g., they're going to vote on X and they're going to approve it! hooray!) it's more likely the decision-makers will feel compelled not to contradict that.
We influence, then, by watching and talking. Easy! Uh, sort of?