Without knowing the full article I cannot be sure. But I think this could be a play of words. The word "Kreuz" on one hand clearly refers to the cross you make on the ballot to vote for a particular candidate.
On the other hand, a cross is also a figure of speech for suffering (of Christ, in particular, and in general). So I would guess that Nadja has difficulty to choose which candidate to vote for because she might be disillusioned with all the available alternatives.
Furthermore, if you say "X hat es mit dem Kreuz" it can also mean that X has problems with his/her back, e.g. back pain, but I cannot see how that ties into the story.