Two Democratic candidates for S.C.’s 1st Congressional seat have scheduled a joint press conference at 11:30 a.m. Monday in Charleston.

Normally, candidates vying to win the same position don’t schedule press conferences with each other, so speculation is that one or the other may drop out and endorse the other for the March 19 primary.

Candidates Martin Skelly and Elizabeth Colbert Busch “will be making an important announcement concerning the 1st Congressional District special election,” according to a press release by Busch’s office.

Busch is the sister of Comedy Central comedian Stephen Colbert and a Charleston business woman. Skelly is a businessman. The only other Democratic contender is perennial candidate Ben Frasier.

Some 16 GOP candidates, the best-known of whom is former Gov. Mark Sanford, are contending in the Republican primary, also on March 19.

Those March 19 primaries will select candidates to run for the seat of former Rep. Tim Scott, R-S.C., who resigned to take the seat of former U.S. Sen. Jim DeMint.

The general election will be May 7.

John Monk