Sen. Henry Jackson (D-Wash.) said recently that he had to "wade through the Senate cloakrooms to get past all the lobbyists." By so saying, he became the only senator of any stature to support the President in his attack on the oil companies and their employees on the Hill.

Carter is currently in a slump. His popularity and the public perception of his performance in various aspects of his job are the lowest ever. The low rating is relfected in senatorial reation to his energy plan and to his defense of it.

In truth, the President never has had a group of stalwarts in the Senate who would follow his lead. On the day after the election last November, this reporter asked Sen. Birch Bayh (D-Ind.) how much support in the Senate Jimmy Carter could count on.

"The Senate will follow him if the country follows him," Bayh said. "But the unique thing about this new President is that there isn't anybody in the Congress who owes him a thing.

So Carter is now planning - so says he is planning - to take his case to the country, and in his attack on the oil companies he has chosen what could turn out to be an extremely popular case. Americans are suspicious of the oil companies, and if the President really means what he says about taking to the hustings, he might possibly turn everything around. Against the oil companies, he will have some good talking points.

He has already lambasted their size, their profits and their growing control over alternative energy sources such as natural gas, coal and nuclear power.

He could tell us also about the taxes oul companies pay; they're lower than those of most other industries because we permit them huge write-offs for exploration and also allow them to deduct the cost of their payments to OPEC for the privilege of bringing out the oil.

He will surely point out that the oil companies control all the intelligence about oil. We don't really know how much domestic oil we own because the oil companies consider that this is "proprietary information." So we may be the only country in the world that doesn't know what's in its own ground.

Finally, the President will have a good talking point when he brings up the the subject of how the oil companies use their profits. They argue that they need more profits in order to look for more oil, but the record doesn't prove that they do this. Their purchases of competing fuel sources and of other enterprised (Mobil Oil recently purchased Montgomery Ward) provide a soft target.

Maybe Carter - if he really means what he says about taking the offensive - can bring the country behind him and in so doing make Birch Bayh look like a prophet. Franklin Roosevelt accomplished this trick more than once, and Harry Truman did it during the election campaign of 1948.

But it will demand a lot more dedication than President Carter has so far evidenced. And it will be complicated by the fact that his energy program is based on forcing up prices to encourage conservation. The same people who will applaud him for attacking robber barons will undoubtedly reflect that if he wins this battle, it will cost them money in higher prices for fuel.

So the campaign Carter says he is about to wage will not seem - as Roosevelt's and Truman's campaigns seemed - a clear question of them versus us. He will have very little help from the Senate, and his record so far on battling for his programs suggests that he will not really carry the battle all the way through.

One felt, as Carter told us about the battle he was about to wage, as though one ought to be saying, "Godspeed, Mr.President." But one found oneself asking instead, "I wonder if he really means it."