So often, both in person and online, I see people asking "can you explain what you mean by..." or trying to break your concern down further. At face value it seems like a good question, but among political types, it almost certainly is a device to either try and reduce your concern to a bunch of little things so small they don't matter, or to tell you you don't understand or have defined something wrong. If you want to stand your ground, its usually better to give nothing, even if you feel like you haven't explained well, or in an online discussion, if you feel like your counterpart has "won" by getting the last comment in.