IN WASHINGTON, where so many people dine out on super-earnest and misinformed political opinions, there is easy money waiting for anyone willing to disturb our arrogant conversation with a few hard facts.

At the next cocktail party, when people are blowing off about the big issues, conservative trends and liberal dilemmas and all that, stick out your chin and say something provocative like this:

"Richard Nixon, for my money, was the best friend poor people ever had."

Your circle of acquaintances may simply drift away, assuming you're gassed and beyond rational conversation. Or they will surround you with outrage, challenge your glibness, demand a retraction.

At this point, they are already hooked. You may confidently offer them a small bet. Such as: The Nixon administration built more low-income public housing for the poor than any of those big-hearted Democratic presidents with all of their liberal promises.

Nobody at this cocktail party, whether they are assembled liberals or conservatives, will believe you. Take their money and tell them to look it up. Page 219 of the Department of Housing and Urban Development's Statistical Yearbook.

While they still have their wallets out, move smartly on to the subject of balanced budgets. Everyone knows that Democrats are the carefree big spenders who fritter away our taxes while Republicans, whatever else they may lack, are good with the bottom line.Therefore, you declare:

"Republicans like to talk about balanced budgets, but the Democrats have a better track record. Harry Truman balanced more budgets than Dwight Eisenhower, but Ike is remembered as a fiscal scold and Truman as a spendthrift."

Nobody will believe this either. Still, it is true. Check the history with the Congressional Budget Office, which keeps track of such things.

While you are chatting with the CBO, ask, by the way, about defense spending under Republicans and Democrats. This is another sure winner.

Democrats are "soft" on national defense and Republicans are stalwarts of the military-industrial complex, right? Wrong. If you look back over the last 30 years, there is one consistent trend in defense spending: Democratic administrations pump up the Pentagon budget and Republican presidents hold it down. Look it up.

My point, of course, is that each of these little-known facts -- and a great many others I could cite -- conflict with the convenient rhetorical assumptions about national politics and policy. You will always hook someone because they have so often heard or read about the speeches which convinced them the opposite is true.

Didn't Richard Nixon tell us himself that he was against all those liberal programs? Yes, he did. And he didn't try to turn them off? Yes, he did. And didn't he succeed until Watergate came along to unseat him? No, he didn't.

If Richard Nixon truly meant to dismantle the Great Society, he failed miserably. He reacted, like any other president before or since, not to his own desires or his party's ideological persuasions, but to the homely realities which confronted him. That included a Democratic Congress bent on standing its ground, an array of existing federal programs churning out money and growing, plus hoary political equations. How many battles can you take on at once? How many groups of voters can you safely aggravate without losing political esteem? m

Considering his expressed views, all those speeches flogging the federal government, Richard Nixon was especially craven in answering those political equations. He let the federal gravy pour and took full credit for it until after his reelection in 1972. Then, safe from the voters, he set about trying to turn off the federal spigots. Too late. Watergate intervened, and we shall never know whether Nixon would have prevailed in his counter-revolution.

I am skeptical myself. The longer I observe government and politics, the more cautions I become about the public rhetoric of politicians, all politicians. This is not because presidents during my brief experience have been especially insincere or mendacious -- though many have been both.

My skepticism is, instead, a modest recognition that events pull in one direction and most political leaders, Republican or Democratic, liberal or conservative or middle-middle, go most readily with the pull of events. On those infrequent occasions when a president stands against the tide, he is often swept away, despite his own intentions.

There are deeper rhythms to politics and policy, powerful dynamics born of momentum, of popular opinion, of supply and demand, of unforeseen disasters, which lie beneath conventional realities constructed from political rhetoric. These rhythms dwarf the supposed differences broadcast by political campaigns and enlarged by the press.

Recently, I came across another stunning example of this crosscurrent. A memo from the White House details what has happened to those experimental programs originated with so much energy by Lyndon Johnson and collectily known as the "War on Poverty." Most people, I would guess, assume that the "war on poverty" ended somewhere, starved of funds and carved up by hostile critics in Congress and the White House.

The present reality is this: The collection of poverty programs were initiated at $800 million in 1965 and grew in one year to 1.5 billion. In the 1981 federal budget, most of these same programs survive, often under different names and different locations in the bureaucracy. But they now consume about $20 billion.

Meanwhile, the number of poor people in America is not declinning, as it did in the 196o's. The government's poeverty count reached its low point -- 23 million -- in 1973 and has risen slightly since.

What happened? What is the implication of those contrary facts? I don't pretend to know fully, but one implication seems inescapable: Whatever good that $20 billion does in aid programs for poor people, it does not do much about eliminating poverty. The "war on poverty" seems permanently stalemated and no longer makes news. The cocktail party talk moves glibly on to other questions.

All of this poses special problems for those of us who are suspended to keep dishing out: slices of reality for public consumption. The best journalism, of course, looks at both layers of reality -- the rhetoric and the underlying dynamics -- when it asks that simple question: What happened? But the news media concentrate first and most heavily on that floating cloud of declared intentions, the daily grist of politics and government.

The dailyness of life is nearly always more immediate and absorbing than a quizzical, ambiguous statement about the long term. I think of a newspaper reporter -- or a politician -- as someone standing on the beach and watching the surf. He will observe with accuracy the riffles and crashes and croossway collisions of the incoming waves. But he may not be able to see that the tide is coming in until his shoes are wet.

Newspapers, like politicians, succumb too easily to the ready-made, the fast fixes. It is a maddening premise, after all, to look at public events, at political candidates and campaigns, at presidents and their policy declarations, and to acknowledge that fundamental realities may be rendering all those words irrelevant, that the cause-and-effect of what's happening in front of our eyes is outrageously complex and, perhaps, unknowable for the moment, maybe forever.

There is a kind of arrogance to the modern dynamics of public opinion -- demanding to know everything, instantly and certainly -- an illusion which is pampered by both press and politicians. So it is humbling to state that the arrogant certainly of cocktail party opinion is nearly always wrong, in one way or another.

Humbling, but not necessarily depressing. Perhaps it is one small step toward democratic wisdom to acknowledge that, beneath all of our good glib talk, we do not know as much as we pretend to know.