I've got news for you. There are far fewer of them than the MSM hype up and they don't make the difference in elections. The ups and downs and swings come from turnout among each side. Remember on average half of people don't vote, but its different people each time. When a sliver more of the conservative non-voters show up we win. When non-voting lefties show up, we loose. It doesn't take much, about 2 or 3 percent.
Undecideds are irrelevant idiots.