Lindsay Clancy could be headed for another courtroom showdown in Massachusetts ... but a former prosecutor says the District Attorney should think twice before running it back.

Jakson breaks down the case on TMZ's YouTube series, "In The Know," with former prosecutor Margaret McLean weighing in on what comes next after Clancy's 11-to-1 mistrial in her murder case.

McLean says the defense's push to have the judge find Clancy not guilty outright is a "real long shot" ... but says prosecutors should seriously reconsider another first-degree murder trial.

She says the D.A. could instead explore involuntary manslaughter rather than risk another hung jury.

As TMZ previously reported, Clancy was back in court Tuesday as her defense argued prosecutors failed to prove she was criminally responsible for killing her three children.

For the full breakdown ... check out "In The Know" on YouTube.