Engaging Iran (And Cuba)

A reader writes:

I've long been a supporter of talks with Iran but have to agree with Roger Cohen, engaging Iran now is the wrong move.  In my mind the purpose of engagement with the regime was less about achieving actual progress on the various serious issues but more about being the adult at the table.  While it might have been possible to get various concessions on small time issues, the US is such a pariah there nothing substantial would ever have been achieved. The regime couldn't do it. 

However, until we acted in good faith with that country, we could never disarm ourselves as the issue and allow for actual Iranian politics to play out.  The point is, what we hoped to have achieved by engaging with Iran has already occurred (partly by walking very softly during their election).  Thus the aim of any talks now can achieve nothing but strengthening the legitimacy of the regime while before talks weakened it.

In fact, the best move I believe the president can make is talking, loudly, to Cuba.  If you can disregard the legitimacy of the stolen election in Iran and push directly for more openness and economic prosperity in an equally adversarial country, there's your carrot and stick, without directly meddling in Iranian affairs.

This is a very potent point. Brilliant even. Any counters?

-- AS