Jimmy Carter in the '08 Obama Cabinet?

If Obama wanted Jimmy in the cabinet for some reason, would Jimmy join? If so, what cabinet role would Jimmy take?

Not sure what effect this would have for Obama popularity wise, but I think by 2008 Carter is held in higher regard than the 80s and 90s, so I'm assuming it would be a net positive, and having someone with presidential experience in the cabinet can't really be a bad thing. That said, Carter was also critical of a lot of Obama's foreign policy decisions such as keeping Guantanamo open and using drone strikes. Carter might be brash enough to say these things even as an active cabinet member, since dropping a former president off the cabinet would be a bad look, if Obama was upset about this.

Also, being a one term president himself, he wouldn't be removed from the line of succession like other speculative post-presidency cabinet members would be.
I was gonna say the mental health of an 84-year-old man might be an issue, but Carter was publishing books, some of them on substantive geopolitical issues, up until a couple of years ago.

Then again, one of those books was a treatise on Israel/Palestine called Peace Not Apartheid. I suspect that title alone would make him persona non grata in the cabinet of a man who was already having to fight off accusations that he was a foreign-born Muslim terrorist.

Plus, the mental acumen required to write a book on venerable old subjects you have a long familiarity with might be a bit different from the mental acumen required to deal with hot-button issues being tossed on your desk in real-time, not to mention shouting matches in cabinet etc.

Finally, Carter is the go-to template for making derogatory comparisons involving Democratic politicians. Pretty sure I remember at least one headline asking if Obama was "another Carter". Turns out he wasn't, really, but that still might not be an image Obama would want to cement in the public consciousness.

On the off-chance he did get into cabinet, I'd he see him in something like Health And Human Services, where he could parlay his humanitarian image for good purposes. He'd probably be good as a backroom adviser on foreign-policy, but I can't see him running Foggy Bottom or the Pentagon. Can you imagine the kind of PR he'd get on any Iran-related issue?