Is it worth engaging with the arguments of someone of whom you do not have an especially high opinion? That depends. If it's just about influencing her (the person in question), maybe not. But if it's about the argument itself and the influence it might have with others, then it could be worth doing.
In a letter in today's Guardian Jenny Tonge responds to a column by Jonathan Freedland in which he wondered at the lack of protest about the Assad regime's brutality and its tens of thousands of victims, particularly from political quarters always quick to condemn Israel when it kills Palestinians. Tonge's response (scroll down) is of the we-expect-more-of-Israel variety:
Jonathan Freedland makes the usual plea "why condemn Israel?". Israel claims to be a western-style democracy that respects human rights and international law. The US and the EU, as well as our own country, have social, academic, cultural and trade links with Israel, and many of us have friends or colleagues in Israel. To many UK citizens, it is their home too. Israel drove the Palestinians from their homeland and livelihoods in 1948 and for 45 years Israel has occupied the West Bank. The treatment of the Palestinians is brutal and humiliating, as I have witnessed. We are right to condemn Israel for its actions. We are right to demand a higher standard of behaviour from Israel than from Arab states that are only now struggling to achieve political change. I have been to Syria. Does Mr Freedland really want Israel to be judged by the same standards by which we judge Syria?
Apart from the fact that Tonge misconstrues the column she's responding to - the point of which was not to object to appropriate condemnation of Israel but to query the lack of condemnation of Syria from many who condemn Israel regularly and vociferously - Tonge's is a very bad argument. Knowing her track record in Israel-related matters, I wouldn't bother if this were just about her. But the argument for higher standards from some countries than from others is one you hear frequently, and so it is worth emphasizing just what it licenses: in the present case, widespread murder and torture, no less. For the higher standards being demanded by Tonge and those who think similarly concern, not the way in which one is to hold one's tea cup on posh occasions or how properly to address religious and other dignitaries, but rather whether or not it's OK to arrest and torture children, massacre civilians, savagely repress political protest, and so forth. There are not standards in such matters that are lower but still acceptable from some sorts of people or states but not from other sorts of people or states. This is because there are universally binding standards, embodied in internationally agreed codes.
The talk of expecting higher standards in this context is just a way of condoning the atrocities perpetrated by some regimes while acts of lesser gravity by democratic states are given the full condemnatory treatment. And that is how it is in this instance. Tonge speaks of 'Arab states that are only now struggling to achieve political change'. So that's what the Syrian regime is up to, is it? Poor old Assad - just give him a little time to catch up.
Human rights standards apply universally, to democratic polities and tyrannical regimes alike. Just as an argument can matter even when the person making it may not be open to having her mind changed, so a binding moral standard is to be insisted upon even when - indeed especially when - some particular regime has gone beyond all civilized constraints.