THE MISSED opportunities and blunders in Melvin H. King's campaign could fill an encyclopedia of ways to loso a mayoral election.

Tomorrow, King will likely he defeated by City Councilor Raymond L. Flynn, who has managed to surmount many questions about his politics and ideology without really answering them.

Flynn will win the Boston mayoral election because he has been abler to convince the voting public that he and the clearly liberal King are essentially the same. They are not.

He will win the election because, for people who are frightened by Mel King's rhetoric and Blackness, he has managed to appear, more or less, as an advocate of the status quo.

The haziness of Flynn's political leanings are defined by the term "urban populist," as he would like us to have it. But the many essential contradictions in his politics and a track record of indecisiveness on social and economic issues indicate more a willingness to follow the polls than to shape them.

So why has this contradiction not been driven home by his opponent?

Along the campaign trail, King has made some major and minor political gaffes, all of which have drawn attention away from Flynn's positions. King told a group of Jewish leaders, for instance, that he would welcome embattled PLO leader Yasser Arafat to Boston "with open arms" if he recognized Israel's right to exist. After the comment drew harsh criticism from the Jewish community, King swallowed his whole leg by trying to extricate himself from the situation.

Speaking again before a Jewish group, King said that an anti-abortion letter released by the much beloved late Humberto Cardinal Medeiros "reflected anti-Semitism" because Rep. Barney Frank '61, who is Jewish, was considered the butt of the cardinal's criticism. But Frank told The Globe that King must have gotten the issue "mixed up" with something else. King was forced to "clarify" and then, finally, apologized for a remark that unjustly criticized one of the Roman Catholic community's most popular public figures.

King, finally, has refused to shut up about his love affair with Cuban dictator Fidel Castro. The then-state representative had been linked with the pro-Soviet leader ever since King missed a crucial tie vote in the House because he was vacationing in Cuba as a guest of Castro. A week before the preliminary, he said on a radio talk show that he "preferred" Castro to President Reagan because Castro had done more to help the poor. He has, himself, brought up the Castro several times since then.

King's nagging, though largely irrelevant, proclivity to speak out on everything from Zionism to nuclear policy has managed to draw voter attention away from a platform which--though still incomplete--is more appealing than Flynn's King was wise this summer to discard the African dashikis in favor of the new Mel King Look--the bowtie and suits--and the change symbolized that he had moved beyond the protest leader state. It is surprising that he did not have the foresight to throw the rhetoric into the trash as well.

This ideological spouting has raised legitimate though probably unfounded doubts about King's unwillingness to compromise with the more entrenched state legislative and city council. No matter what King's politics and are on issues relevant to this city, his hubristic attempts to be a national political figure have clouded serious questions about Flynn's substances. Flynn is quite simply, not the progressive he purports to be. .

Take several examples. In 1973, Flynn opposed efforts in the state senate to create a minority district in Roxbury and desegregate the all-white senate. He now calls himself a supporter of minority rights.

In 1974, he proposed legislation in the state house of representatives to abolish mandatory education, a move designed to counteract court-ordered busing, which he opposed. He still opposes busing on philosophical grounds and claims that his actions in 1974 were only an attempt to "provide a voice" for his constituency.

Flynn toed the conservative line on social issues, coming out against ERA and abortion, and for capital punishment. He now has changed his views on ERA and the death penalty, but is steadfast on abortion. In short, while Flynn says he has grown since his early days as a South Boston state representative, the rapidity of his political shift raises serious concerns that he is no more than an opportunist.

But King, who naturally appeals to the city's more intellectual and chic liberal residents, has been largely unable to communicate exactly what makes him different from Flynn. And, probably out of fear of alienating the much-needed white vote, he has not effectively criticized Flynn's opposition to the institution of court-ordered busing in 1974.