The whole NK arc was...BLAAAAHHH.
My interpretation of what Martha really meant when she called Lois and interrupted the would-be lovemaking is of course just my own interpretation, but I stand by it. I get the impression that it was moderately late when Martha called and that Clark and Lois were, probably, at Lois's place. Well, as I understand LnC canon, Martha and Jonathan are supposedly very happily married, which definitely suggests to me that they have an active love life. So what would Martha and Jonathan have done themselves if they had been about to be separated, possibly forever? They would be making love, right? Particularly if it was the night before Jonathan had to go. Now Martha is calling Lois on the night before Clark is leaving for Krypton - what was she thinking? Didn't she understand that Clark and Lois wanted the night for themselves? Couldn't she understand that they wanted to make love?
Bear in mind, too, that this fic doesn't suggest that Martha had pleaded with Clark not to go with Zara. I conclude, therefore, that she hadn't tried to make him think that his real duty might be to be the husband of Lois and the guardian of the Earth. If she didn't say it - and I don't get the impression that she did - then she really silently agreed with Zara that Clark had to go to Krypton. At least that's how I read it. And I think Martha must have
known that she was interrupting something between Clark and Lois when she called on that particular night, and and she must have known that her son and his fiancée wouldn't be able to recapture the moment and return to intimacy after her phone call. So the way I see it, Martha was really saying, though not in so many words, that Clark should not be making love with Lois (and indeed she had just made sure that he wouldn't) and that he should, indeed, leave her and Jonathan and Lois and the Earth and go to Krypton and marry Zara and be a general and a Lord instead. To me, that is pretty indistinguishable from casting him out.
I agree with you, Darcy, that Clark was forced to leave because of his own character. He has a big Messiah-complex, as Happygirl pointed out, and therefore he couldn't turn down Zara's call for help
and marriage, if he thought that he needed to be Zara's husband in order to be able to help the people on New Krypton. Clark has an almost compulsive need to help, which is why other people, like his parents, should have pleaded with him and made him see things differently. Happygirl, I loved your Jonathan speech!!!
Clark did have one very legitimate reason to go to New Krypton, however. Of course he would want to meet other Kryptonians, other people like himself, and see a Kryptonian society. And... yes, indeed... he would want to help those Kryptonians. That's Clark for you.
Ann