The introduction of another superhero. Yet again, one who knows about Clark's abilities from the outset. By the time Clark becomes a superhero, a lot of his colleagues will already know who he is.
Lex is backing the bad guy;
Lionel learns Kal-el's secret and will keep it because of his respect for Martha.
It makes sense that a security camera will have recorded Clark rescuing Lana from a fire and that a security guard will try to blackmail Martha with the video. Lionel lies when he tells Martha that he does not know what is in the video but the main point is that he will not tell anyone else.
Surely there should have been another election before Martha took Jonathan's Senate seat?