In his now-celebrated Los Angeles speech on lawyers, the president quoted from one of his favorite philosophers, Reinhold Niebuhr. Like Niebuhr, he said, he has learned that "It is the sad duty of politics to establish justice in a sinful world."

Upon his return to Washington, the president's press secretary testified to another sad duty of politicians - to recognize the difficulties, if not the limits, of leadership and yet still attempt to gain support for needed public policies. The example cited was the president's new voluntary anti-inflation program. It was said to be "in doubt" because few business and labor leaders seemed willing to make the necessary sacrifices to slow wages and prices.

Jimmy Carter and Jody Powell are certainly correct about this, and they don't have to single out business, labor and lawyhers to prove their point. A closer, more vivid example of the apparent inevitability of soaring inflation lies here in the nation's capital. For a shock a day all you have to do is glance at the latest real estate ads. If you're really masochistic, go out and see what's happening to the Washington housing market.

Then, wonder where and how the inflation spiral stops. We're in the midst of a sustained boom. No one dares raise the specter of a bust.

Last weekend a house in the Cleveland Park section of Washington went on the market. The price: $450,000. It was, an envious competing realtor says, snapped up that same day - for cash.

At the same time another realtor reports another sale in that same section. This one was for an old house needing complete repairs and renovation. The price: $200,000.

Across the Potomac, in Arlington, a townhouse went on sale. It was built a year ago.So many potential buyers showed up that even even the veteran agent found the situation "unreal." A contract was placed on the house the same day. The purchasers put down $100,000 in cash.

A week ago the real estate sections carried ads from a firm offering two houses in Bethesda priced in the quarter-million-dollar range. Both are now sold.

The same pages announced a new development "in sight of the Potomac River". pre-opening prices began at $146,800. A call to that agency elicits the information that only one of those houses - a model - has been constructed, but that now is the time to get a "really fantastic buy." Houses there, it's explained, are being built in from 90 to 120 days. The best buy of all will be in the third section, one actually offering waterfront lots. The beginning price there: $400,000.

In Northwest Washington, a knowledgeable realtor explains, the lowest price range for a house considered barely inhabitable is from $75,000 to $100,000. That means a modest row house. In the central city, where neighborhoods are being "renewed," but not by the government, people are paying from $65,000 to $75,000 for what an agent calls "just a bombed-out shell." On and on, up and up. Prices are jumping by about 15 to 20 percent a year, and sometimes as much as $1,000 a month.

"Nobody ever thought we'd see the prices we're seeing today," says Tony Scrivener, who will sell you a house starting at a low price of $112,000 and going all the way up to an embassy property listed at $725,000. "The market's going crazy. There are several factors. The pressure on this city comes from all over the world. Everybody's coming to Washington, everybody wants to be in the city. And this pressure is building. We now have more real estate agents than houses."

Scrivener and others in the business make the point that, while the Washington area prices are extraordinary, the increases are only a reflection of rising housing costs acrosss the country. Inflation is everywhere.

What makes Washington special, and instructive, are other factors. The area rests upon an almost recession-free economy propped up by the federal government. And its population is composed solidly of professional people, with many couples pulling down two high incomes. But more intriguing are the kinds of people Scrivener and others find themselves dealing with in today's booming real estate market. There are, it seems, more and more lawyers, doctors and consultants coming into the capital. These are people drawn here to do business with the government. As Scrivener says, only half jokingly, "between attorneys and real estate agents, I don't know who else is in town."

It was a young doctor, a Virginia realtor says, who put down a substantial downpayment recently on a Cleveland Park property, a diplomat who laid out a huge cash sum for an Arlington house, a young lawyer who has bought and sold three times in three years even-rising profits.

"There are so many doctors and lawyers looking for better tax shelters these days," this realtor says, "and they are finding them in real estate. They are investing in housing properties as hedges against inflation. It's the best investment around."

What we are creating, it appears, is a mandarin class, the likes of which the world hasn't seen since antiquity.

In his classic "Decline and Fall of the Roman Empire," Gibbon writes:

"Juvenal laments, as it should seem from his own experience, the hardships of the poorer citizens, to whom he addresses the salutary advice of emigrating, without delay, from the smoke of Rome, since they might purchase, in the little towns of Italy, a cheerful, commodious dwelling, at the same price which they annually paid for a dark and miserable lodging. House-rent was therefore immoderately dear; the rich acquired, at an enormous expense, the ground, which they covered with palaces and gardens; but the body of the Roman people were crowded into a narrow space; and the different floors and apartments of the same house were divided, as it is still the custom of Paris and other cities, among several families of plebians."

That kind of doleful situation may not have been the kind of situation Jimmy Carter had in mind when he made his speech to the lawyers a few days ago, but his larger theme, as I get it, is worth restating. It is, as Carter put it:

"This morning new inflation figures were published in Washington that caused me grave concern. How can we, the privileged members of American society, call upon the working people, the men and women of our country, to make a financial sacrifice to deal with inflation unless attorneys, doctors, accountants and other professionals, presidents, assume the same responsibility to assist in our efforts to keep a lid on inflation?"

How, indeed?