Washington (CNN) Kentucky's Republican Party voted Saturday to move their presidential nominating event from a May primary to a March caucus -- a victory for Sen. Rand Paul, who will be able to seek re-election to the Senate while continuing his White House bid.

A Kentucky law prevents a candidate's name from appearing on the same ballot more than once, so Paul could not run for Senate and president on the same primary ballot. Attempts to change the law failed, so Paul pushed for the Kentucky Republican Party to change the presidential primary into a caucus and move it earlier in the spring.

The change is estimated to cost between $400,000 - $600,000, according to Scott Lasley, Kentucky GOP 2nd district chairman.

"Sen. Paul reaffirmed his intent to pay for the caucus. $250,000 is to be raised or transferred to (the Republican Party of Kentucky) by September 18. If the money is not there by the 18th, it will revert back to a presidential primary instead of the caucus," Lasley said in an email to CNN. "Details on the remaining balance will be determined as the process unfolds."

Paul praised the party's decision in a statement Saturday afternoon.

"The people of Kentucky deserve a voice as the GOP chooses their next nominee, and holding a caucus will ensure that Kentucky is relevant and participates early in the process," he said in a statement. "I am also grateful for the Republican Party's trust in me, allowing me to run for re-election to the U.S. Senate and seek the nomination for the Presidency of the United States."

The Kentucky GOP executive committee unanimously advanced the proposal in March, charging a special committee with developing a plan for how the change would actually be implemented.

Many members felt that moving to the caucus would boost the state's importance in the primary, which would make for a more exciting race than most presidential years.

Paul sat atop the GOP field in a CNN/ORC poll conducted in March 2014, and had support in the double-digits as recently as April of this year, but in the most recent CNN/ORC poll this week , just 6% of Republican registered voters said they would support the Kentucky senator.

Current GOP front-runner Donald Trump took to Twitter earlier this month to tease the senator over the change.

"Why is @RandPaul allowed to take advantage of the people of Kentucky by running for Senator and Pres. Why should Kentucky be back up plan?" Trump tweeted.