MARYLAND WAS disgraced last year by a scandal at the Baltimore jail in which violent prison gang members colluded (and in some cases had sex) with corrupt correctional officers to engineer a virtual takeover of the facility. A contributing factor in the breakdown of order was that jail management found it all but impossible to discipline guards suspected of misconduct, thanks to a state law that guarantees them elaborate procedural safeguards.

That law, known as the Correctional Officers’ Bill of Rights, should have been a cautionary tale for lawmakers in Annapolis. Unfortunately, under union pressure, they are flirting with repeating the mistake — this time for police officers.

A bill drafted by the Fraternal Order of Police would force investigators to throw out any evidence of police brutality, corruption, racial profiling or other serious abuses if they made even a technical mistake while looking into suspected wrongdoing. Police chiefs and sheriffs around the state, most of whom oppose the measure, say the bill would undercut their efforts to weed out bad cops and promote public trust in their departments.

The measure, sponsored by Sen. Brian E. Frosh and Del. Kathleen M. Dumais, a pair of Montgomery County Democrats, would provide police officers facing internal disciplinary action or firing with protections usually reserved for accused criminals looking at prison time. Even in Maryland, where public employees have extensive rights thanks to their political clout, no other group of state or local workers is covered by such safeguards.

The bill would expand the existing “Law Enforcement Officers’ Bill of Rights,” from which Maryland police officers and sheriff’s deputies have benefited for the past 40 years. That measure, one of the most extensive in the nation, tips the scales heavily in favor of uniformed officers suspected of misconduct by providing stringent procedures in the course of internal investigations.

In general, the current rules have worked well, although they have added fuel to a process that is so highly litigious that it often takes a couple of years or more to discipline an officer once he is suspected of wrongdoing. But it is going too far to add an “exclusionary rule” that would ban any evidence collected if investigators committed even a garden-variety technical violation of the rules.

For instance, what if an officer were informed of the names of possible witnesses nine days ahead of an administrative hearing instead of the 10 specified ? S hould that be reason to toss out all evidence of serious misconduct gathered by investigators? What if the officer is not officially informed of the name, rank and job title of a fellow officer present during his interrogation, perhaps because the two have known each other for years — should that also be sufficient to quash evidence? Lawmakers seem prepared to consider watering down the bill, and they should. By automatically excluding such evidence, they would make an unwieldy system positively sclerotic and give bad cops a free pass.