WASHINGTON (AP) _ The Supreme Court said today it will decide _ sometime in 2000 _ whether a runoff election is needed to determine Guam's governor.

The justices said they will review rulings that stripped Gov. Carl Gutierrez, the Democratic incumbent, of the victory he thought he had won last November.

The court granted an appeal in which Gutierrez and Lt. Gov. Madeleine Bordallo seek to avoid the runoff election against Republican former Gov. Joseph Ada and his running mate, Felix Camacho.

The case will be argued this winter.

A federal judge and the 9th U.S. Circuit Court of Appeals ruled that a runoff election is necessary because 1,313 blank ballots deprived Gutierrez and Bordallo of the absolute majority they needed.

Guam is a U.S. territory about 3,700 miles southwest of Hawaii. Gutierrez and Ada were the only two gubernatorial candidates in last November's election. Gutierrez received 24,250 votes; Ada 21,200.

Federal law requires a territorial governor to get ``a majority of the votes cast in any election,'' and Guam's Election Commission declared Gutierrez the winner by a slim margin after adding about 1,900 write-ins and defective votes to the total.

Ada sued, contending that the 1,313 ballots on which no votes were cast in the governor's contest but were marked for other races had to be counted as ``votes cast in any election.'' Counting those votes would leave Gutierrez 83 votes shy of a majority.

U.S. District Judge John Unpingco ordered a runoff, and a three-judge panel of the 9th Circuit court unanimously upheld his ruling.

``Congress presumably would not have included the phrase 'in any election' if it meant to refer only to the votes cast in the single election for governor and lieutenant governor,'' the appeals court said.

In the appeal acted on today, lawyers for Gutierrez and Bordallo noted that the exact wording appears in a federal law governing gubernatorial elections in the U.S. Virgin Islands, and that a federal appeals court ruled that ballots do not count unless marked for the territorial governor's race.

The case is Gutierrez vs. Ada, 99-51.