The problem with liberals and progressives, says Rep. John Conyers Jr., is not that they don't have ideas or commitment. The problem, he says, is the absence of a solid electoral base capable of electing the sort of public officials who could transform their ideas into legislation.

He thinks he knows what to do about it. The Detroit Democrat has started a political action committee whose unique purpose is to train and provide financial assistance to new black and progressive candidates, particularly in the South. He has named it the Parker-Coltrane Political Action Committee, after the celebrated jazz saxophonists Charlie Parker and John Coltrane.

"There are quite a few liberal PACs in existence," he said recently, "but I have found, unfortunately, that none of these will focus on the South; nor will they pay special attention to black candidates."

The reason, no doubt, is that progressives have conceded the South to the conservatives--a concession Conyers thinks is a major mistake. Blacks hold the balance of power, if not absolute electoral majorities, in scores of Deep South congressional districts. Yet only two of the 18 black members of Congress come from that region. Parker-Coltrane could help to change that, Conyers believes.

"We are focusing our initial work in the South for a number of reasons," he said. "It is the area of the largest number of black Americans; it has had a tremendous expansion in the number of black-elected officials (thanks to the 1965 Voting Rights Act); it is home to very powerful conservative politicians, and it is an area that shows real potential for political change."

The new PAC, which filed with the Federal Election Commission only a few months ago, sent a delegation to Mississippi last month to lay plans for a two-day candidate training seminar next March. With the aid of elected black officials in the state, political experts and labor leaders from across the country and money from Parker-Coltrane, the idea is to recruit, coach and finance likely black candidates.

The PAC's first major fund-raiser will be held a month from now in a Washington jazz club, Blues Alley. Conyers hopes to clear some $12,000- 14,000.

Parker-Coltrane is distinct from the still newer Congressional Black Caucus Political Action Committee. "I like to think we influenced, in a positive way, the formation of the CBC PAC, which, of course, will focus on incumbents, rather than the support of new candidates," Conyers said. "I should mention that Parker-Coltrane is a necessary complement to the CBC's political strategy of networking and pressure politics."

The committee's name stems from two facts: first, Conyers is a dedicated jazz buff, with a special fondness for the innovative stylings of the late Parker and Coltrane. Second, he hopes to enlist the assistance of black performers in the PAC's fund-raising efforts. Singer Nancy Wilson, for instance, will be the guest artist at the $100-a-ticket Blues Alley affair.

"Politics is everybody's business -- including people who dig great jazz or disco or spend their weekends watching football or basketball on television," he said. "It isn't the exclusive property of a few ambitious people who are concerned about their private interests more than the people's interest."

As a civics lesson, Conyers' view is unassailable. But translating into political action and fund-raising will be a major test of the congressman's skills. Blacks have yet to establish a tradition of giving money to political campaigns. One reason may be the fact that blacks have less money to give--which is why Conyers is smart to tap black entertainers. He is also reaching out to organizations of middle-class blacks. Delta Sigma Theta Sorority, for instance, will co- sponsor a political training conference in North Carolina next May.

Conyers thinks that the support will be there once people come to realize the potential not just for electing a few new politicians but for changing the political climate--much as has been done in the opposite direction by the National Conservative Political Action Committee and the Moral Majority.

"We expect to see a quickening of the political pulse in the black community, once this operation gets rolling," he said.