That... seems like a pretty accurate, if brief, summary of when defamation is actionable under this Act. (Disparaging - yup, s.1; outright lies - yup, s.2; etc.). Do you come to bury the act or to praise it?
This shows the limits on speech freedom in the USA http://en.wikipedia.org/wiki/United_States_free_speech_excep...
In the UK we also enjoy the fact the politicians can't just outright lie in their Manifesto about other candidates or the current government. If/when they do, action is taken to correct or (when maliciously undertaken) to disqualify that person from running for public office.
It's pretty creepy to see some on HN so adamant about limiting free speech.
e.g. s106 Representation of the People Act 1983 ("False statements as to candidates.") http://www.legislation.gov.uk/ukpga/1983/2/section/106
Everything else is fair game and "personal character" is narrowly construed — it's about "the man beneath the politician" as one court put it.
There's also no legal bar to lying about your intentions in your manifesto, despite a few attempts to persuade the courts to create one.
This from the High Court of England and Wales — "Can a promise of this kind give rise to an enforceable legitimate expectation? Even if we had accepted that the relevant ministerial statements had the effect of a promise to hold a referendum in respect of the Lisbon Treaty, such a promise would not in our view give rise to a legitimate expectation enforceable in public law, such that the courts could intervene to prevent the expectation being defeated by a change of mind concerning the holding of a referendum. The subject-matter, nature and context of a promise of this kind place it in the realm of politics, not of the courts, and the question whether the government should be held to such a promise is a political rather than a legal matter." (Wheeler v PM, a case about whether the PM was legally obliged by a manifesto commitment to hold a referendum on an EU treaty http://www.bailii.org/cgi-bin/markup.cgi?doc=/ew/cases/EWHC/...)
(IANAL).