Supreme Court Justice Clarence Thomas has amended his financial-disclosure forms after a liberal group, Common Cause, said he was failing to report the employment of his wife, conservative activist Virginia Thomas.

Associate Justice Clarence Thomas (AP Photo/Pablo Martinez Monsivais)

In filings dated Friday, Justice Thomas asked court officials to amend disclosures going back to 1989, when he served as a federal appellate-court judge. An item on the forms asks judges to disclose any “noninvestment income” for their spouse. The form asks only for the name of the employer or other party paying the spouse and doesn’t seek a dollar figure.

Justice Thomas had checked “none” for that item, but now he wants the forms to reflect the names of the employers for whom Mrs. Thomas worked, including the Heritage Foundation from December 1998 through October 2008.

Justice Thomas wrote that the information about his wife’s employment “was inadvertently omitted due to a misunderstanding of the filing instructions.”

Common Cause said it was “implausible” that a justice who interprets complex legal matters “misunderstood the simple directions of a federal disclosure form.”…