The answer is: defend. The whole purpose in a<em> Persuasive Essay</em> is to try to <em>convince</em> the readers about certain things. This requires that the writer take a firm position, <em>defending his points</em>. He doesn't present the other side, but, because he believes he is suggesting ideas that will make things better, he invites participation and advises that if the ideas are not embraced, things might not get better.