(1) the tweet-detail page, for the tweet that includes the link;
(2) the t.co mapping, so that the tweet-detail page's t.co link can somehow be resolved to the (archived) page to which it links.
I don't think there are any blocks against doing (1).
Unfortunately for (2), Twitter has a blanket robots.txt prohibition in place for domain t.co. Perhaps IA could be convinced to ignore that robots.txt in the public interest.
Alternatively, perhaps another site could be set up that itself accepts t.co link-paths, in the background queries t.co, and returns both an HTML page and working redirect that isn't robots.txt-blocked. LinkArchiver (and any other similar sites) could as a convention archive responses of this other site whenever they'd like to archive t.co.
(1) the tweet-detail page, for the tweet that includes the link;
(2) the t.co mapping, so that the tweet-detail page's t.co link can somehow be resolved to the (archived) page to which it links.
I don't think there are any blocks against doing (1).
Unfortunately for (2), Twitter has a blanket robots.txt prohibition in place for domain t.co. Perhaps IA could be convinced to ignore that robots.txt in the public interest.
Alternatively, perhaps another site could be set up that itself accepts t.co link-paths, in the background queries t.co, and returns both an HTML page and working redirect that isn't robots.txt-blocked. LinkArchiver (and any other similar sites) could as a convention archive responses of this other site whenever they'd like to archive t.co.