; and (B) by inserting before the period at the end the following: or designate a Senior Justice in accordance with section 294(e) to fill a vacancy resulting from the retirement of a justice under this section ; and (2) by adding at the end the following: (f) Any justice of the United States who has served a total of 18 years as a justice shall be treated as a justice retired from regular active service under this section, unless the justice is otherwise eligible to retire as a result of a disability under section 372. . (b) Disabled justices Section 372(a) of title 28, United States Code, is amended in the first sentence, by inserting after a successor the following: or, in the case of a justice of the United States, fill the vacancy in accordance with section 294(e) .