Voters cannot make an educated choice if they don't have information about the candidates.  Thankfully, according to MassLive, all candidates on the general election ballot for the special election for Massachusetts' US Senate seat will be allowed to participate in all debates.

According to the MassLive article:

"Brown, Coakley and Kennedy will face off in the first televised debate on Tuesday. The debate will be taped, and is scheduled to be aired on WBZ-TV Channel 4 in Boston from 8 to 9 a.m. on Dec. 27 and on WSBK-TV Channel 38 in Boston from 7 to 8 p.m. on Dec. 28.

Brown and Kennedy also have confirmed they will attend a debate on Jan. 8 in Springfield sponsored by WGBY-TV Channel 57. Coakley, who grew up in North Adams, is also expected to attend.
The debate in Springfield is scheduled to be taped and then aired from 7:30 to 8:30 p.m. on Jan. 8."

Democracy takes one small step further.