AS AN EXERCISE in high-minded detachment, President Carter's Tuesday night talk on energy was a model. He turned the other cheek to those senators who have sliced up this bill. He overlooked the grim struggle - the parliamentary equivalent of trench warfare - now going on the in conference between the House, which passed something like his original plan, and the Senate, which notoriously did not. Mr. Carter's tone was moderate, and his terms were mild. But there are times when high-minded detachment is not what the Presidents' job requires. The energy speech represents, unhappily, an opportunity lost.

It was an opportunity to focus, forcefully, the attention of this nation on the sources of its prosperity and welfare. It was an opportunity to point out to voters their stake in the House-Senate conference. It was an opportunity to let the conference know, explicitly, what he expects and requires of it. He laid down three "standards" for the bill. But those standards were made of sponge rubber, and they leave the impress that they could be fitted to almost anything that the conference might choose to produce.

Mr. Carter touched on the relationship between his bill and employment. But he touched on it only briefly and, again, mildly. Isn't employment the main point of this whole excruciating legislative exercise? The President was making a crucial point, although he was making it in a monotone. It's not just the shortages and embargoes of oil that cause unemployment. The present tremendous trade deficit, owed wholly to the outpouring of wealth for imported oil, is depressing the entire American economy and slowting the rate at which it creates jobs. Mr. Carter offered the highly instructive comment that a rise of $5 billion a year in oil imports means a cost of about 200,000 American jobs. This year's oil imports will run about $13 billion higher than last year's. As a result, unemployment will be about half a million jobs higher than it would have been if the country had held oil imports to last year's level. Mr. Carter didn't speel out the point. He touched it briefly once - and never came back to it.But the President's job at this point is, above all, to show the rest of the country why restraint is essential.

Mr. Carter is determined to avoid the polemic styles of some of his recent predecessors. He judges, quite correctly, that Americans grew exceedingly wearly of Chicken Little speeches suggesting continually that the sky was about to fall. But understatement has its own perils.

The conference is in trouble because a lot of the conferees' constituents don't see any reason for all of those fierce new taxes. "What is being measured," Mr. Carter said, "is the strength and will of our nation." But national will proceeds from a sense of national necessity, and a great many Americans still don't see why an energy plan is needed. After all, there's plenty of gasoline at the filling stations.

In the absence of national will, the course of the conference will be determined by the opposite quality - what you might call national won't, a grumpy and suspicious resistance to any change in the accustomed order of things. Mr. Carter has an urgent message for this country, but he is delivering it very softly. You can barely hear it.