DAVID MILGAARD has been in Canadian prisons since 1969, and for many of the intervening years he has watched his advocates struggle to overturn his murder conviction. But now his case is gaining high-profile news media coverage in Canada."Has Canada's justice system failed David Milgaard?" wonders the lead headline in The Toronto Star for Aug. 11. And in The Globe and Mail, Canada's leading national newspaper, a three-part front-page series that ended Aug. 24 repeatedly asks: "Did justice fail?" in Mr. Milgaard's case. These new press reports seem likely to boost politicians who want Milgaard's case reviewed. And there are signs the case could become a partisan political issue. The Parliament member who monitors justice issues for Canada's opposition Liberal Party, Russell MacLellan, says a Conservative Party official's refusal to reopen the case is "inane." "Our party has lost patience in the matter and when the House [of Commons] reopens on the 16th of September, we're going to go at this with everything we have." He says Liberal members will take the case to the prime minister if necessary. Milgaard is serving a life sentence for the Jan. 31, 1969, murder of Gail Miller, a nursing assistant in Saskatoon, a city in Canada's Saskatchewan province. His legal appeals were exhausted by the end of 1971, but since then a key trial witness has recanted, physical evidence has been discredited, and a possible perpetrator of the crime has been identified by lawyers and investigators working on Milgaard's behalf. Michael Jackson, a University of British Columbia law professor who has handled another wrongful conviction case, says that front-page publicity and the political debate it can cause are necessary steps in the process of reversing mistakes by the legal system. Once appeals are exhausted, he says, a convict's "only opportunity is when the media takes an interest and says, 'Look, there's a problem here.' " "When the House [of Commons] goes back in session ... there'll be some questions on Milgaard," says Stephen Aronson, an Ottawa lawyer who won exoneration for a man who spent 11 years in jail before his murder conviction was overturned. He agrees that publicity and politics are important to any reversal. "The political play of this [case] will make it very difficult for the government to press its 'He got a fair trial' line," says Brian Schwartz, a constitutional law professor at the University of Manitoba in Winnipeg, where Milgaard's family lives and near where he is incarcerated. Professor Schwartz also ventures that it is "quite likely that [Milgaard] will be extricated from jail fairly soon." New press accounts have "further solidified public opinion" in favor of Milgaard, says John Harvard, a Liberal Party member of Parliament, who has long supported Milgaard's attempt to have his case reviewed. Of "the letters I do get, I would say 99.9 percent ... say it looks like this is a case of maljustice," Mr. Harvard says, "and that at the very least the case should be reopened." Milgaard's lawyers have exercised a Canadian law that allows a convict to petition the country's minister of justice for a special review of a case that has exhausted its appeals. Minister of Justice A. Kim Campbell, a Conservative Party member, in February denied one such appeal by Milgaard, but his lawyers have filed another, using new information that is also part of recent press accounts. The revelations concern the crime history of former Saskatoon resident Larry Fisher, who is now serving a sentence for rape and attempted murder. Mr. Fisher is scheduled for release in 1994, and has denied any role in the Gail Miller murder. He has not responded to press inquiries for several months. But Milgaard's lawyer, David Asper, contends that a series of sexual assaults confessed to by Fisher is "so startlingly similar to the Gail Miller murder that you're almost drawn to an inescapable conclusion." At the same, however, he cautions, "We've got to be careful here ... [Fisher] is still presumed innocent." Canada's Justice Department says it will investigate Mr. Asper's new petition. But the lawyer says his client is not buoyed by the ups and downs in his case. "What's happening to him is cruel beyond belief," he says of Milgaard. "He's not coping very well."