Citizens Union urged New Yorkers on Tuesday to vote against the proposed constitutional amendment to raise the retirement age for some judges.

The civic watchdog group said its opposition is based chiefly on the fact that the amendment would apply only to elected Supreme Court justices and judges appointed to the Court of Appeals instead of all state judges. Citizens Union said there is no “principled reason” for letting those judges stay on the bench until they are 80 while continuing to require all other state judges to step down at age 70.