WASHINGTON — Don't look for a quick winner in the race for the Republican presidential nomination next year.

The Republicans have adopted a new rule designed to extend their nominating process this time around.

The rule limits the ability of candidates to win large numbers of delegates in primaries and caucuses held before April. Delegates must be awarded in proportion to the votes a candidate receives. States with winner-take-all rules will have to wait until April to hold their primaries.

In 2008 Democrats successfully rode their drawn-out battle between Hillary Rodham Clinton and Barack Obama all the way to the White House.

GOP leaders hope an extended nominating contest will energize party activists for the general election.