Suing your criminal defense attorney just got a lot tougher in Washington state.

Last month, the state Supreme Court ruled that before you can accuse your lawyer of malpractice, you have to prove you didn't commit the crime.

"Your protection is based on the fact that you have been harmed," explained Anne Bremner (search), a well-known Seattle criminal defense attorney. "And you're not harmed if you're guilty."

The case at issue involved psychiatrist Jessy Ang and his wife Editha, who sued their lawyers for convincing them to plead guilty to felony fraud.

The Angs, who own a medical-examining company, had been accused of making false diagnoses of mental illness that enabled patients to collect welfare and Social Security benefits. The couple eventually hired new representation, went to trial on the charges and were acquitted on all counts.

But the Angs' malpractice lawsuit against their old lawyers failed because they couldn't prove they didn't do it.

"I'm always of the belief that we're innocent until proven guilty," explained Jessy Ang. "If we are not proven guilty, logically we're innocent."

The Supreme Court of the State of Washington, in a 5-4 decision that generated three dissenting opinions, disagreed.

"The Angs were properly required to prove by a preponderance of the evidence that they were actually innocent of the underlying criminal charges," states the majority opinion, written by Justice Susan Owens (search). "We find no persuasive reasons for this court to follow the minority position and shift the burden to the defendant attorneys to prove that their former clients were actually guilty of the charged crimes."

In other words, the justices decided that the Angs' acquittal didn't mean they were innocent — only that the government had failed to prove its case.

Requiring the Angs to prove their innocence, the majority opinion argued, ensures that the guilty cannot commit a crime, get off, and then profit from that crime.

Attorneys, like the court, are divided.

Robert B. Gould (search), a Seattle attorney who specializes in legal malpractice and who represented the Angs in their lawsuit, says the state Supreme Court ruling is unprecedented.

"What this case does is create virtual immunity," explained Gould, "a safe harbor for criminal defense lawyers."

The ruling puts criminal defense lawyers, who normally champion their clients' innocence, in the position of arguing the opposite in civil court.

One Supreme Court justice who voted against the decision fears that the ruling will protect incompetent or legitimately negligent attorneys.

Justice Tom Chambers (search) wrote in his dissent that he felt "indignation" that the court "would carve out a special protection for criminal defense attorneys whose acts of professional negligence are harmful to their clients. ... Those of us caught in the grip of the law are always entitled to competent legal representation whether or not we are totally innocent."

Defense lawyers object to the notion that the ruling will shield incompetence.

"They would never, in my mind, [while] upholding their own oath, make some decision [that], 'I'm going to do less of a job because he can't sue me anyway,'" said Bremner. "Because that's not what drives lawyers. It's a profession, not a business."

The Angs are now asking the state Supreme Court to reconsider a ruling that makes them both not guilty — and not innocent.

Click in the video box above to watch a complete report by FOX News' Dan Springer.