A "good argument" refers to a well-reasoned and persuasive presentation of ideas, supported by evidence, that can help convince others to agree with or consider a certain viewpoint. Full definition
I am not an atheist, but this kind of story could make a real good arguement for it. (religion.blogs.cnn.com)
We had good arguements for keeping Hayward on the wasatch, but when you're heart is somewhere else, there isn't much that is going to change that. (sbnation.com)