I am not a teacher, but am well-read.
The iron frame and all that in the context of a government would, I think, refer to those people or things that form the solid base of the government that are not easily swayed or changed. To say that the iron frame was rusting and buckling would indicate that even the very foundation of the government was starting to give, as even iron does not last forever. In this case, the administrator saying "it is up to us to keep it going" after saying it is rusing and buckling would indicate that he doesn't have a lot of faith in his ability to hold it up himself.
To say something "smacked of a build-up to a showdown" can be broken in to separate explanations. Lets start with showdown -- which is a confrontation. A build-up to a showdown would indicate that events were leading up to a confrontation. To "smack of" means to "certainly appear as if", so overall the statement indicates that "His supporters resented his action because it appeared to them as if he was leading up to a confrontation."
Finally, you have the emphasis wrong on the statement "Im pained at the twist given to the debate". To be pained means to be upset by something. When something is given a twist, it means that the intended meaning has been altered, so the statement could more simplistically be read, "It upsets me that the context of the debate has been altered." For example if you were listening to a debate on politics, and it turned into a debate on religious belief instead, you would say that you were pained at the twist given to the debate, if in fact you were annoyed that they ended up arguing over religion.
Sorry its so wordy. I hope this helps