Following a practice that began in 1962 with a year-end interview with President Kennedy, the three major television networks, on December 19, 1967, carried a joint hour-long interview with President Johnson. Senator Eugene J. McCarthy, who had prior to that broadcast announced his own candidacy for the Democratic Party’s presidential nomination, requested “equal time” on the ground that President Johnson was a legally qualified candidate for the same nomination within the intent of Section 315 of the Communications Act.1

The Federal Communications Commission denied the Senator’s request.2 The ruling was based on the Commission’s regulation interpreting Section 315 as applying only to legally qualified persons who had, among other things, publicly announced their candidacies.3 There being no question that President Johnson had not announced his candidacy, the Commission refused also to give Senator McCarthy the opportunity to prove that President Johnson was acting as a candidate in fact. Senator McCarthy petitioned this court under 47 U.S.C. § 402(a) to review the Commission’s ruling and, in view of the rapidly approaching state primaries, moved for summary reversal. For reasons which follow, we deny this motion.

The purpose of Section 315 is to require a broadcaster to give equal treatment to all candidates for a particular office or nomination once the broadcaster’s facilities have been made available to any one of the candidates.4 Petitioner does not contend that it is unreasonable to require, as a condition precedent to invoking the benefit of the statute, that the claimant to equal treatment announce his candidacy. Petitioner argues, however, that it is another matter if a candidate deprives his op*474ponents of the benefit of the statute simply by withholding an announcement of his own candidacy.

Since Congress has delegated to the Commission the duty to implement Section 315, our review is limited to determining whether the Commission’s long-standing regulation is unreasonable or in contravention of the statutory purpose. In making this determination, “This court is not at liberty to substitute its own discretion for that of administrative officers who have kept within the bounds of their administrative powers.”5 This is particularly true where the Commission has been assigned a responsibility of the kind here involved.

The obvious difficulty in determining whether a likely public figure is a candidate within the intent of the statute justifies the Commission in promulgating a more or less absolute rule. If the application of such a rule more often than not produces a result which accords with political reality, its rational basis is established. But no rule in this sensitive area can be applied mechanically without, in some instances at least, resulting in unfairness and possible constitutional complications.

As we read the Commission’s rulings, if the President had announced his candidacy prior to the December 19 program, petitioner would be entitled to equal time irrespective of the content of that program.6 But program content, and perhaps other criteria, may provide a guide to reality where a public figure allowed television or radio time has not announced for public office.

Considering the content and the timing of the not unprecedented year-end interview with the President, we cannot say that the application of the Commission’s rule in this case without the requested hearing produced an unreasonable result.

Affirmed.7