NOW IT GETS TOUGH. As President Carter said, it was an unpleasant talk. Energy policy - as long as there wasn't any -remained a subject for polite and pleasant discussion. Conservation? By all means let's have some. Increased supplies? We need that, too. New technologies? The more the merrier. But now Mr. Carter is pushing Congress and the country toward a rigorous and specific program of self-protection. The details and costs are becoming clearer. Suddenly the discussion is turning into a hot quarrel. You can hear the protests already: Why us, and not somebody else? Why now, and not later?

"If we wait, we will constantly live in fear and embargoes," the President answered last night. "We could endanger our freedom as a sovereign nation to act in foreign affairs. Within 10 years we would not be able to import enough oil - from any country, at any acceptable price . . . Inflation will soar, production will go down, people will lose their jobs." He's right. The crucial thing is whether his listeners were really listening.

President Carter is undertaking the most difficult of all exercises in democratic leadership. he is trying to persuade a large and rich nation to prepare for a crisis that is not yet entirely visible from street level. Those preparations are necessarily expensive and disruptive. The crisis exists already, and the statisticians can chart its steady increase in scale and menace. But most people aren't statiscians, and as long as there's plenty of gasoline at the corner filling station it's hard to believe in the reality. Furnaces will click on faithfully when the temperature drops, and there's light when you turn of switch. So where's the crisis?

That is the task of persuasion to which Mr. Carter has now set himself, vigorously and courageously. He began last night to explain to Americans the urgent necessity of taking control of his country's runaway consumption of fuel. On Wednesday, his message to Congress is to lay out in detail the mechanisms of the program - the new taxes that will hit everybody, the rebates, the uncomfortable constraints and conditions. On Friday at his press conference he will continue that advocacy - and, we might add, throughout many months to come.

Congress is in no mood to hurry. Most members of Congress understand perfectly well the jeopardy in which past delay has placed the American economy. They know that the huge oil price increases three years ago, and the Arab embargo, were the main reasons for a severe recession from which the country has not yet recovered. They know that last winter's natural gas shortage threw a million people out of work, and that there's worse to come. But Congress also knows that a great many voters regard access to cheap gasoline as a basic freedom, not a matter of economics, and others just don't see what the fuss is about. There's an enormous weight of misunderstanding and resentment for Mr. Carter to move.

Congress wants to wait for a bit to see which will win - Mr. Carter, with his engineer's mind and his sophisticated planners, or the great human inclination to wait until it starts raining again before deciding whether the roof still needs patching. Mr. Carter has made, in political terms, a huge investment in this energy program. His ability to move it toward enactment will affect the whole character of his presidency, as long as he remains in office. But there is far more at issue here than the political standing of one man.

It would be infinitely foolish of the rest of us Americans to think that we enjoy the luxury here of being spectators at someone else's prize fight. No President or Congress can enact legislation as sweeping as the energy program without a very broad measure of public agreement. It's a test not only of the President but of the country, and whether it can agree on self-imposed restraint without waiting for another catastrophe like the oil-induced recession of 1973-75. It's not only the job at the White House that's at stake. It's also jobs, incomes, and stability of living standards for people all over the United States.