U.S. Rep. Stephen Lynch and his Democratic challenger square off in another "mini-debate" lasting 15 minutes.

Milton Democrat Mac D'Alessandro and Lynch will be on WGBH's "Greater Boston" show tonight. The show airs at 7 p.m.

D'Alessandro's campaign says their opponent has declined other debate invitations, including for a half-hour on New England Cable News. D'Alessandro appears live on Broadside with Jim Braude tonight at 6 p.m. The show re-airs at 8 p.m.

Lynch and D'Alessandro previously sparred on WBZ-TV in another 15-minute "mini-debate" on Aug. 27.