At a press conference yesterday, state Attorney General Martha Coakley minced no words about Annie Dookhan, the state chemist accused of tampering with drug samples in thousands of criminal cases:

Annie Dookhan’s alleged actions corrupted the integrity of the entire criminal justice system. There are many victims as a result of this.

But only four years ago, Coakley argued before the US Supreme Court that defense lawyers should not be allowed to force people like Dookhan to testify in court because their lab results did not constitute “testimony” whose author could be compelled to discuss under the Sixth Amendment right to confront one’s accusers.

Lab results are so reliable that the only real question, she argued in the case of Melendez-Diaz v. Massachusetts, is whether the substance a chemist says is a drug came from the defendant, not whether it was a drug or not. At one point in her arguments over the case, which involved a Boston man convicted of drug dealing in 2001, Coakley said the result of a lab test “becomes almost secondary to the case.”

From the transcript of Coakley’s appearance before the court:

JUSTICE SCALIA: It’s very important to know whether indeed this was the particular substance that was taken from the defendant. And to establish that, you have to establish a line of custody. And you can’t do that without getting in the person who did the test.

MS. COAKLEY: Well, Your Honor, I agree the chain of custody is crucial and it relates to the careful procedure that a police officer used, who by the way is the confrontation witness that you worry about because the behavior is the buying, selling, possession of drugs. The element of whether it is cocaine or not really becomes almost secondary to the case. The issue is was the behavior criminal? So the officer who seized the drugs is available for confrontation. The drug is then clearly marked so the Commonwealth has to create that chain of custody for the court, and indeed if the defendant, who is in the best position to think that perhaps this is involving something other than cocaine or heroin, has all the opportunities that he needs to make sure that he gets a fair trial.

JUSTICE SCALIA: He says — the policeman says, “And I gave it to the University of Massachusetts lab.”

MS. COAKLEY: And they marked it in a particular way that identified —

JUSTICE SCALIA: “And I watched when they marked it in a particular way.”

MS. COAKLEY: And the —

JUSTICE SCALIA: How do I know that that thing is the one that got to the desk of the analyst who wrote this report?

MS. COAKLEY: I think that whether you brought the analyst in or not, you would have the same establishment of the chain of custody and, indeed, that piece of evidence as to whether it’s the same drug relates to the officer in this case testified the packaging. He could identify it. It comes back —

JUSTICE SCALIA: So you say you can require witnesses to show that, right up to the analyst who did the testing, you can require witnesses to testify? All the way up to there but not the analyst himself?

MS. COAKLEY: I think, Your Honor, that the issue between chain of custody and whether the Confrontation Clause is implicated are different issues

In her brief to the court before the arguments, Coakley wrote why a lab certification without testimony from the analyst who performed it did not violate a defendant’s Sixth Amendment rights:

It is decidedly lacking here because drug analysis certificates do not accuse anyone of anything criminal; instead, they merely establish the current physical composition and weight of a chemical substance. These neutral, objective facts become inculpatory only when a testifying witness, who is properly subject to confrontation, provides the necessary evidentiary links to connect the substance tested in the laboratory to the accused’s past criminal conduct.

She cited an 18th-century English criminal case:

A leading English criminal case, decided shortly before the Bill of Rights was adopted, explained the theory behind the official records exception in similar terms:

The law reposes such a confidence in public officers that it presumes that they will discharge their several trusts with accuracy and fidelity; and therefore whatever acts they do in discharge of their public duty may be given in evidence and shall be taken to be true.

By a 5-4 vote, the high court disagreed with Coakley, which led to a number of cases in which the Massachusetts Appeals Court and Supreme Judicial Court reversed drug (and gun) convictionsbecause prosecutors’ cases relied so heavily on certificates from state technicians.

Yesterday, a few hours after Coakley’s press conference, the Suffolk County District Attorney’s office announced it plans to drop charges against an accused drug dealer because the substance Dookhan certified was cocaine was, in fact, something completely inert.

Given this experience, I wonder if she would argue the same position today?