How will the controversies between North and South Korea affect the US?

The tension between the two Koreas are frightening because although they are not skirmishing at the moment, they are technically still warring, and something bad could happen at the right opportunity. This affects the US because we are allies with South Korea, and if any sort of war breaks out spontaneously, we could very well be dragged into the situation. According to CNN, the US troops at the DMZ have been working with the South Korean militia on defensive tactics in case anything does happen. Apparently, Kim Jong Un found this offensive, so now the tensions are steeper than ever. The American government is under enough trouble, isn't it? If we get into a war we don't really need to be involved in, even if we are allied with South Korea, it will be a strain on the economy as the government would have to fund military operations,and it might even be detrimental to the American people if the fighiting comes this way.