Of course, we do not want to throw out the baby (Church Militant) with the bathwater (Church Belligerent). Because we do have to fight. But how should we fight? How do we wield the sword without impaling our souls on it?
First (and last), we must be willing to suffer. It is not our job to correct everything. And trying to do so will only bring unrest. Yes, this means that at times we will have to bear wrongs and allow errors to go uncorrected. There are many rotten things in the Church, but none of them are of the Church. We must suffer to see the weeds among the wheat.
Second, holiness of life is essential. Again, the true battle is not out there, but within. J.R.R. Tolkien’s Lord of the Rings provides a good image of true and false battles. In that trilogy the big, exciting scenes are of enormous armies arrayed for battle. But the more important storyline is that of the two hobbits quietly making their hidden way to destroy the ring. Their inconspicuous, unseen mission is the real battle, without which the armies of light are destroyed. So also for us. The most intense battle, the most difficult mission territory, the first place to be reformed, is hidden and unseen: the heart. And unless we tend to that first, all else is for naught.
Third, we should draw inspiration from and follow the example of the warriors who have gone before us. First among these, of course, is our Lord himself. He certainly fought—with the devil, with the scribes and Pharisees, with death itself. And he was capable of severity. Yet he directed his harshest words and actions not at prostitutes and tax collectors, but at religious hypocrites. He commands us to learn from him not because of his severity but because he is meek and humble of heart (cf. Matt. 11:29). Yes, he cleansed the temple, but he also wept over Jerusalem.In some ways, I'm reminded of Peter Kreeft's talk on how to win the culture wars: the answer is to become saints. This is not to take the foolhardy route of saying (with the Sojourners and any number of other liberal Christians) that the way to win a culture war is not to fight one, but rather it is to say that it can't be a total war. The only "total war" which we can wage is against our own sins, our own demons, and even this can't really be won without turning to God first.
When it comes to the culture, to other people, we have to remember that winning arguments is not the real endgame: winning souls is. And winning souls is not something which we can do by ourselves. It's certainly not something we can do by argument alone, and an argument pushed too hard, absent compassion, absent personal witness, will likely as not push the person on the receiving end away. Arguments (meaning here a vigorous defense of doctrine) are sometimes good for catechesis--that is, teaching about the faith to people who are already at least somewhat sympathetic. They also are necessary in apologetics--defending the Faith from an attack, often with the knowledge that there are others around than the two people involved in the argument.
But arguments and particularly polemics have a much smaller place in the process of evangelizing people. This process of evangelization involves winning both hearts and minds, and is best accomplished through personal witness, tactful (and honest) discussions, and of course prayer (it is God and not us Who ultimately wins the soul).