DOES THE FEDERAL Trade Commission have the power to initiate complaints against suspected violators of the antitrust laws? Since the FTC was created some 70 years ago, almost everyone has supposed that the answer was yes. Now comes into federal district court a former Reagan administration Justice Department official to say the answer is no. Theodore B. Olson, who as head of the office of legal counsel was in effect the attorney general's attorney, is now one of the lawyers for several title companies the FTC wants to investigate.

The title companies want the district court to quash the investigation, on the grounds that the FTC has no power to bring "quasi-prosecutorial" actions. That power, they say, belongs strictly to the president and his appointees and, since the president can't remove an FTC commissioner from office except for cause, the FTC is trying to exercise powers the Constitution says it may not have. Attorney General Edwin Meese, in a speech last fall, seemed to take a similar position. "It should be up to the president to enforce the law," he said. "We should abandon the idea that there are such things as 'quasi-legislative' or 'quasi-judicial' functions that can be properly delegated to independent agencies."

What's odd here is that conservatives are so ready to overturn decades of practical experience on the basis of what is, at best, a novel and theoretical argument. Novel, because it is based heavily on two recent Supreme Court decisions, the 1976 case upholding the federal campaign finance laws and the 1982 case overturning legislative vetoes. Theoretical, because it takes the Constitution's broad command that the president "shall take care that the laws be faithfully executed," and constructs from it a barrier against any law enforcement or even investigatorial proceeding brought by an agency whose members the president can't fire. One wonders whether such powers, under this theory, can be delegated to officials with civil service protections.

More important, this theory, if valid, could remove all enforcement powers from such agencies as the Securities and Exchange Commission, the Consumer Product Safety Commission and the Interstate Commerce Commission. This is a bizarre result, and certainly one not contemplated by any president or Congress in the 99 years since the first of these, the ICC, was established.

The Olson argument is a cousin of the argument made by such diverse sources as the Justice Department and, in a lawsuit already filed, Rep. Mike Synar (D-Okla.) against the Gramm-Rudman Act. The claim is that Congress cannot delegate to the General Accounting Office, an agency clearly outside the executive branch, the power to declare by how much the budget must be cut if Congress does not act. For decades presidents and Congresses have been establishing agencies that combine functions associated with the different branches of government; now the courts and some politicians are trying to build high walls around each branch.

It has been assumed that the great battles ahead in the Supreme Court would be over issues like abortion and criminal procedure. Now it looks as if the courts will be called on to decide whether to join in overturning agencies of government that have endured for decades and about whose powers only a few litigants have voiced complaints.