Usually the "relation back" principles of FRCP 15 are meaningful only to particular civil litigants who have filed an amended complaint. But because habeas petitions are technically civil actions, the contours of this rule sometimes make a dispositive difference in a prisoner's liberty. So it's important to get them right.
The majority and the dissent here disagree on how best to apply these principles. Here's how the first paragraph of the dissent concisely frames the issue:
"Proceeding pro se, Ronald Ross filed a federal habeas
petition a few months before his time to do so under the
Antiterrorism and Effective Death Penalty Act of 1996
(“AEDPA”) was set to expire. His form petition asserted
ineffective assistance of trial counsel on several grounds,
including failure to secure a speedy trial, to assert prejudice
from evidence lost before trial, to retain defense experts, and
to object to the state’s experts. Ross’s petition contained no
specific factual allegations, but he attached to his petition a
six-page state-court decision that discussed the factual bases
of most of his claims in some detail. The majority holds that
Ross’s amended petition—which he prepared with the
assistance of counsel but filed several months after AEDPA’s
deadline had passed—does not relate back to the date of his
original petition because the original petition set out no facts.
See Fed. R. Civ. P. 15(c)(1)(B) (providing that an amendment
relates back if it asserts claims that arise out of the “conduct,
transaction, or occurrence” set out in the original pleading)."
The majority thinks there's no relation back. Check out the opinion to see if you agree.