WASHINGTON — Senator Rand Paul succeeded on Saturday in persuading the leadership of the Republican Party in Kentucky to help him resolve a predicament that could threaten his plans to run for president in 2016: a state law that prohibits candidates from appearing twice on the same ballot.

To avoid running afoul of the law, Mr. Paul asked the state party to suspend its presidential primary, scheduled for May next year, and hold a caucus instead, a decision the party’s executive committee adopted on Saturday. A caucus would help Mr. Paul in two ways. First, it is likely to be held well before May, meaning it could assist him in building his delegate count early in the Republican nominating contest. Second, because caucuses do not require actual ballots, it resolves the main legal question.

Mr. Paul, the junior senator from Kentucky, has said that he intends to run for re-election while pursuing the Republican nomination for president. The move to a caucus system would relieve him of having to give up his seat.

“Today the Republican Party of Kentucky took a big step toward holding a presidential caucus in 2016,” said Doug Stafford, Mr. Paul’s senior political adviser. The vote, Mr. Stafford added, was unanimous.