TALLAHASSEE, Fla. (AP) — Sen. Bill Nelson believes that the only practical way to settle the state's delegate mess is to hold a second Democratic presidential primary by mail, his chief of staff said Saturday.

The state has three options to try to seat its delegates at the Democrats' national convention: Hold another primary at the polls, vote by mail or hold caucuses, said Nelson chief of staff Pete Mitchell.

A primary would be too expensive and would require the Republican-led Legislature to approve it. Caucuses would be difficult to organize in a state as large as Florida, especially since the state isn't used to holding them. Also, caucuses wouldn't draw nearly as many people as the 1.7 million who voted in the Jan. 29 primary, Mitchell said.

"We're trying to research that mail-in option," Mitchell said. "There's high level discussions taking place."

On Thursday, Nelson, who supports New York Sen. Hillary Rodham Clinton, called for a new primary, though he didn't suggest how it should be held.

Nelson met with his staff Saturday to discuss logistics. The effort to try to seat the state's delegates at the August convention has become more critical as the race between Clinton and Illinois Sen. Barack Obama has hit a deadlock.

"Nothing is going to work unless the campaigns mutually agree," Mitchell said, adding Nelson has "tried everything — a lawsuit, he's pleaded and cajoled and we're still stuck."

The Democratic National Committee stripped Florida and Michigan of their delegates because they violated party rules by holding primaries before Feb. 5. Now the DNC is suggesting the states hold some sort of do-over in order to seat delegates.

"It looks like it could be done," Nelson spokesman Dan McLaughlin said after the meeting. "What you need now in Florida is the will, but you can't go out and muster the will until (DNC Chairman) Howard Dean goes out and gets the two campaigns to agree."

The state party considered a vote-by-mail option months ago, but the cost was too high. The original plan called for two postcards to be sent to each of the state's 4.1 million Democrats to give them notice of the plan before sending ballots out. That would have cost an estimated $8 million. If only the ballot is sent out, the price could drop to $4 million, Mitchell said.

Nelson's office has been speaking to party officials in Oregon about how they handle voting by mail and it's encouraged by what they've heard, Mitchell said. It's still unclear where the money would come from to pay for the vote.