That said, I liked this trilogy. It's actually rather chilling in that it really resembles relations between Iraq, Iran, and the US after the Second Gulf War. Way ahead of its time.
I'm probably really showcasing my ignorance here, but I don't see the connection.
You can think of Iraq in this instance as Bajor--fractured and with tons of infighting, the US in the place of the Federation, trying to help the Iraqis find stability (think of the time before things started going better in al-Anbar Province), and the Iranians in the place of the Cardassians. Granted, the Iranians never occupied Iraq, but there is no doubt they want to expand their power into that area. And like the Cardassians did in the Circle Trilogy, they covertly fund Iraqi insurgents in hopes of taking down the Iraqi government and indirectly striking at the US.
So aside from the fact that the Iranians never occupied Iraq, the parallel fits.
That's far out man! Firstly the Cardassians could give the Federation a bit of a bloody nose in war, the Iranians can't even do that. Secondly Iraq is not all like Bajor, because most of the in-fighting is religious based, Sunni vs Shia, at least the Bajorans are united through their faith. Plus the USA ain't no Federation either... It's a very dodgy anology...
Anyway I thought Invasive Procedures was average, but after the circle/Bajor trilogy such let down was inevitable... The funny thing is that there is a one in two chance that Verad was compatible without having to go through any of that Trill symbiosis commission BS about finding the correct host for a symbiont. So Verad was right to be pissed (as he was biologically compatible), and would be even more so if he knew the commission's dirty little secret...