It seems a cruel coincidence that we celebrate St. Agnes, a Roman virgin martyred at 13 and a patroness of innocents, on the day before the anniversary of the legalization of murdering innocent children in America. I suppose the juxtaposition is a good reminder to ask for her intercession, though: for the children, for the mothers who feel like they don't have any other choice, for conversion of heart in all those who do not find abortion reprehensible.
Will seeing the many people attending the March for Life in D.C., or participating in local prayer vigils or rallies, suddenly convict legislators of the evil of abortion? Probably not---although we know better than to limit what God can do! But there's always a chance that some passers-by will wind up wondering why these people care enough about the issue to stand out in the cold, find themselves looking for answers, and experience a change of heart. And, too, we know that "Where two or three are gathered in My Name, there am I in their midst." Coming together to pray for an end to abortion is certainly valuable, even when we can't see visible results.
Whatever you to do mark tomorrow, don't forget: "In all the dioceses of the United States of America, January 22 shall be observed as a particular day of penance for violations to the dignity of the human person through acts of abortion, and of prayer for the full restoration of the legal guarantee of the right to life." GIRM, no 373.
And, parents: Don't miss Simcha Fisher's Ten Ways to Raise Pro-Life Children over at the National Catholic Register!