The American philosopher Daniel Dennett outlines an extremely effective process for arguing with someone who has opposing views:
(1) Attempt to re-express the other person’s position so clearly, vividly, and fairly that they say, “Thanks, I wish I’d thought of putting it that way.”
(2) List any points of agreement (especially if they are not matters of general or widespread agreement).
(3) Mention anything you have learned from your target.
(4) Only then are you permitted to say so much as a word of rebuttal or criticism.