Tough internal politicking by Federal Communications Commission Chairman Charles Ferris may preserve a Carter-Mondale Election Committee attempt to force reluctant television networks to sell President Carter a half-hour of prime time next month to announce his candidacy.

The FCC has already ruled once for the Carter campaign, finding 4 to 3 last week that the networks acted unreasonably in refusing to sell Carter the time he requested on any of the four nights he requested, Dec. 4 through 7.

The networks argued that the request was for too much time, and too soon, in view of the tough ratings war they are engaged in.

If they sold Carter the time, the networks said, they would have to sell similar blocks of time to several other candidates asking for the same exposure.

Instead, ABC offered a half hour in January, CBS offered five minutes at 10:55 p.m. on Saturday Dec. 8, and NBC offered nothing.

The Carter staff panicked. Being scheduled to coincide with the announcement were more than 2,300 house parties at which a total of as much as $11 million could be raised.

And the networks wouldn't even return telephone calls from Carter's advertising man, Gerald Rafshoon.

Finally, because the houseparty hosts needed to send out invitations, the committee settled on Tuesday, Dec. 4, as the night of the announcement. Still the networks refused to sell any time, choosing instead to appeal last week's FCC order that they act in a more reasonable manner and find time for Carter's show.

On Monday, rumors began to circulate that one FCC commissioner who had earlier voted in favor of the Carter-Mondal committee. Democrat Tyrone Brown, might switch his vote on the technical reason that two of the networks did offer something, thus showing some reasonable attempt to cooperate.

Brown was in Geneva at the World Administrative Radio Conference when the story of his possible defection made its way around Washington. Chairman Ferris placed a hurried intercontinental phone call, and they talked for an hour. And, as soon as Brown returned to the United States yesterday afternoon, Ferris was back on the phone to him.

Although no one is talking about that phone call, Ferris indicated later that it was his impression that a vote of the commissioners today would be the same as last week's, favoring Carter.

On top of that, Ferris said, if the vote is the same, the commission would likely draft a "tight order" for the networks to offer Carter some air time, and soon.

If the networks still do not comply, Ferris said, the FCC would be left with no alternative but to begin revocation proceedings that could result in withdrawal of broadcast licenses from the five television stations owned by each network.