LITTLE ROCK — In a closely watched special election in northeastern Arkansas, Republican John Cooper defeated Democrat Steve Rockwell for the state Senate seat vacated by Democrat Paul Bookout amid an ethics scandal.

In unofficial results, Cooper received 57 percent of the vote and Rockwell garnered just under 43 percent. Less than 17 percent of the more than 45,000 registered voters in Senate District 21 cast ballots.

The winner could cast a key vote in the Legislature’s fiscal session next month on Arkansas’ "private option" for health care expansion under the federal Affordable Care Act.

The plan to use Medicaid dollars to subsidize private insurance for the state’s working poor passed the Senate with just one vote to spare in the 2013 regular session and needs a three-fourths majority in the House and Senate to be reauthorized for the fiscal year that begins July 1.

Bookout voted for the private option. Both candidates in the special election to replace him campaigned heavily on the program — Rockwell favoring the private option, Cooper vowing to vote to defund the program.

Bookout resigned from the District 21 Senate seat in August after being reprimanded and fined $8,000 by the state Ethics Commission for converting thousands of dollars in campaign contributions to personal use. A special prosecutor is reviewing the case to determine whether criminal conduct occurred.