Whether a state court's ruling that an unpreserved claim of federal constitutional error does not meet the requirements of the 'plain error' standard is subject to case-by-case review in a federal habeas corpus proceeding to determine if the ruling rested primarily on, or was interwoven with, the merits of the claim

QUESTION PRESENTED Whether a state court’s ruling that an unpreserved claim of federal constitutional error does not meet the requirements of the “plain error” standard is subject to case-by-case review in a federal habeas corpus proceeding to determine if the ruling rested primarily on, or was interwoven with, the merits of the claim. i