Yes, it absolutely should be. Politics is not just old men arguing. It is your life. They are deciding how you will live, what you will do, how you will be treated and every single other thing about your life. Should they be punished for misrepresenting what they will do or are doing? Yes, absolutely.
No, it should not be against the law for people in politics to lie to us, because politicians would be too afraid to say anything. Enforcement would become political. This is similar to every new president who wants to impeach the one before, if they happen to have different politics than the president before them. This is just an attempt to stifle free speech.