ALBANY — State Senate Republicans won a political victory yesterday when a court ruled that the house can add a 63rd seat next year.

State Supreme Court Judge Richard Braun called the addition “disturbing” but constitutional.

Observers say the extra seat would bolster the GOP’s chance to defy a 2-1 voter-enrollment disadvantage this fall and keep its only power base in state government.

Senate Dems said they’ll appeal.

Republicans hold a 32-29 majority, with a special election to fill the current Brooklyn seat of convicted ex-Sen. Carl Kruger, a Democrat, too close to call.