The marble palace of the Federal Reserve Board has a kind of extraterritorial status in Washington. The seven members of the board live in their Greek temple, and presidents may come and go but they remain, serving 14-year terms. They get their power because they can enlarge or diminish the money supply. This is less complicated than it sounds. The board sits at the monetary faucet that controls the amount of credit, a little twist to the right or left can put workers back on their jobs in Detroit or send Wall Street into a tizzy.
It is an anxious job, subject to criticism. In everyday language the Fed can make credit ''easy'' or ''tight.'' It is supposed to provide enough money to finance an adequate rate of growth but not enough to create inflation. If the Fed sees economic slackness it can make credit cheaper and try to stimulate business. If it sees inflation getting out of hand (as it has recently) it can close the faucet of credit supply. Either way there are shouts and new debates. One of the debates is whether the Fed should be independent. This has been going on for years.
On July 22, 1958, for example, Prof. Seymour E. Harris came down from Harvard to tell the House Committee on Government Operations: ''The Federal Reserve Board still insists upon its independence and the President (Eisenhower). . . not only fails to suggest policy in the monetary field but even insists upon the desirability of a system which allows and encourages one policy in the monetary field and another in non-monetary fields.''
And so on. Dr. Harris pointed to an unquestioned anomaly. No other nation could operate our system of government. We give Congress the power to override the president, we give the president power to veto the Congress; we give the Supreme Court power to chastise both. The Fed is just another separate enclave of power. The theory is that power over the credit supply is too great to be left to ordinary ''politics'' so set up an independent agency to handle it on a non-partisan basis.
Theoretically the system is just as uncomfortable for a Democrat as a Republican. Is the Democrat more partial to big-spending, is the Republican the one who is austere and parsimonious? At present it is a Republican President who is in trouble over big deficits. But that isn't really fair, says Ronald Reagan: the deficits are left over from spending policies of predecessors, he asserts. The nation can argue it out.
Meanwhile there are new proposals to end the Fed's independence. Here is one from Sen. Alan Cranston (D) of California, a redeemed journalist who once helped cover Europe for the international news service, and who ultimately came to the Senate in 1968. (He now hints of presidential ambitions.) ''It's inconsistent with representative democracy,'' Senator Cranston said recently, ''to have seven people appointed to 14-year terms on a board with vast, sweeping powers over the lives and fortunes of the American people - a board which is accountable not to the electorate, not to the President, not to Congress.''
He is right, it isn't consistent with ''representative democracy'' in the ordinary parliamentary sense, but it is consistent with the separation of powers in which Washington abounds. Said Prof. Michael D. Reagan of the University of California way back in 1967, the Fed's independence is an ''unwarranted, anachronistic, ineffective and undemocratic element in our society.''
Others think it is effective, however, and a fine system: the debate has been going on for years. Senator Cranston is the latest to enter it. ''We don't give generals the power to declare war,'' he says, quoting economist Milton Friedman. ''Money is much too serious a matter to be left to the central bankers.''
That's the situation now as Wall Street worries and unemployment grows. The Fed has attacked inflation and prices are coming down. Is the achievement worth the price? A clash between President Reagan and Fed Chairman Paul A. Volcker seemed imminent a month ago but may have been settled. Meanwhile complaints about the independence of the seven vestals in their marble temple go on - as usual.