1.) “How to Play” tells you that women whose name begins with “J” are Democrats. So Julie and Jill are Democrats.
2.) Since Jill tells you that everyone in her column voted Democrat or Republican, you know that Derek voted. Julie tells you that either he or Andrea did not vote. Therefore Andrea is a nonvoter.
3.) According to Andrea, Tom and Ben voted the same way. According to Jill, Ben either voted Democrat or Republican. According to Julie, all four corners are different, so Tom could not have voted Democrat. Therefore both Tom and Ben voted Republican.
4.) According to Julie, all four corners are different, so Lisa must have voted for an other party.
5.) According to Ben, one column has nothing but Democrats and possibly nonvoters. It’s clearly not the first, fourth, or fifth columns. According to Tom, Julie must be adjacent to at least two Republicans; one of them would have to be in the second column. So the column that contains only democrats and possibly nonvoters is the middle column. According to Lisa, Pablo definitely voted, so he voted Democrat. You also know that the only other Republican who could be adjacent to Elise (who must be adjacent to at least two according to Tom) is Amanda.
6.) Pablo tells you that Christi and David both voted. Ben tells you that if they voted, they voted Democrat. So Christi and David are both Democrats.
7.) Christi says that Martin and Scott did not both vote. Tom says that Julie is adjacent to at least two Republicans. She is only adjacent to three cells, so Kevin must have voted Republican.
8.) Kevin tells you that Olivia did not vote Republican. Jill tells you that Olivia voted Democrat or Republican; therefore Olivia voted Democrat.
9.) Tom tells you that Andrea is adjacent to at least two Republicans, so Derek and Steve are Republicans.
10.) David tells you that there are four nonvoters, none of whom is adjacent to another. According to Steve, Andrew voted. According to Lisa, Elise voted. According to Christi, Martin or Scott did not vote; therefore Henry and Greta both voted. If Arthur or Aaron did not vote, there could not be four nonvoters who are not adjacent to each other. Therefore the nonvoters are Andrea (already known), Martin or Scott (already known), Bridget or Lauren, and Jared.
11.) According to Tom, Greta must be adjacent to two Republicans. One of them is Martin or Scott, whichever one is not the nonvoter. According to Jared, Henry voted Democrat or other party, so not Republican. Ben says that Bridget did not vote Republican either, so Arthur must have voted Republican.
12.) According to Arthur, no one voted Republican in the middle row. According to Tom, Amanda is adjacent to at least two Republicans; therefore Elise voted Republican.
13.) Elise tells you that both Andrew and Henry are Democrats because they did not vote for an other party according to her, they did not vote Republican according to Arthur, but they did vote according to Steve/David. Jared also tells you much more plainly that Henry voted Democrat.
14.) According to Henry, Aaron is a Democrat because according to Christi and Tom, either Scott is a nonvoter and Martin is a Republican or vice versa.
15.) Andrew tells you to figure out who won the election. At the moment there are 9 Democrats and 8 Republicans. You know that Scott and Martin are Republican and nonvoter and you know that Bridget and Lauren are Democrat and nonvoter. So even if Greta is Republican, the election would be a tie. Therefore Martin and Amanda did not vote the same. So Martin is a nonvoter and Scott voted Republican.
16.) Scott tells you that the election was won by one vote. If Greta voted Republican, the vote is a tie. If she voted Democrat, Democrats won by two votes. David says that Greta did vote since she is adjacent to Martin, so she voted for an other party.
17.) Greta and Ben tell you that Bridget did not vote, since that column can have no Republican.
18.) According to Ben and David, Lauren voted Democrat.