For the purposes of this debate, I take the sign of a poor argument to be that the negation of the premises are more plausible than their affirmations. With that in mind, kohai must demonstrate that the following premises are probably false:
1. Whatever begins to exist has a cause.
2. The universe began to exist.
3. Therefore, the universe has a cause.
We come first to premise (1), which is confirmed in virtually ever area of our sense experience. Even quantum fluctuations, which many suppose to be uncaused, are causally conditioned in that they depend on the existence of a pre-existing quantum vacuum. Indeed, if we suppose (1) to be false, then there is nothing preventing just anything and everything from popping into existence anywhere and at any time. But obviously this doesn't happen -- the universe exhibits regular law-like behavior.
In fact, we see that (1) is a logically necessary truth, the denial of which is self-contradictory. As David Oderberg argues:
We are asked to countenance the possibility of the following situation: the nonexistence of anything followed by the existence of something. The words “followed by” are crucial — how are they to be interpreted? What they cannot mean is that there is at one time nothing and at a subsequent time something, because the nonexistence of anything is supposed toinclude time: to say that at one time there is nothing whatsoever is self-defeating because it is to say that there is a time at which nothing exists — hence something did exist. But it is hard to see how else we are supposed to understand “followed by”; or when the denier of the causal principle says that it is possible for something to come from nothing what are we to understand by “from”? Again it cannot have a causal sense because something is supposed to have come into existence uncaused. All that appears to be left is a timeless contradiction — the existence of nothing and the existence of something. 
Moreover, even if it was shown that there could be such things as effects without causes (Nevermind that it would destroy the idea of causal regularity as we see it), this only barely scratches the KCA. We can simply recast the argument in inductive terms, arguing that it is probable that whatever begins to exist has a cause, and from that draw the conclusion that the universe probably has a cause. Even this less stringent formulation of the KCA is enough to satisfy the conditions of being a good argument.
Dan Barker (Who my opponent is sure to cite), argues that P1 is question-begging because the only member of the class of objects which do not begin to exist is God. Hence P1 becomes "Everything except God needs a cause." However, this criticism is grossly off-point. First, the modified-P1 is simply not logically equivalent to P1. If we recast the KCA using M-P1, then the argument becomes structurally invalid. Second, M-P1 confuses meaning with reference. The two premises may refer to the same object, but...