At the Solidarity Day speaking, all the expected people, the likes of Lane Kirkland and Coretta King, said the expected things about the cruelty of Reagan's budget cuts. What was missing was a clean-up speaker from Wall Street, someone in pinstripes to say what Ronald Reagan hates to hear most about his economic policies--that they don't work.

No one on the podium put in a word for the last, best hope of the host on the Mall, which is the working of the free marketplace on Reagan's supply-side theories. Wall Street is as strange an ally for the 250,000 marchers as it is an adversary for Ronald Reagan. Labor and its friends have to rethink their favorite folk enemy, Wall Street, just as Ronald Reagan has to take a new look at the erstwhile exemplars of western capitalism.

Naturally, the president, who fled to Camp David for the weekend, did not enjoy the spectacle of legions of citizens, many of whom had voted for him last November, protesting policies which he keeps saying have not been tried.

But Wall Street's resistance to his "economic scenario" is the "unkindest cut of all." He feels betrayed, as well he might, having done what he did for them in the tax cut they now say is too big. Wall Street is not self-conscious about having decanted legions of lobbyists to push for the tax cut's passage--it got its share of goodies. But during August, when the market fell, Wall Street had a chance to look at the figures, and turned its back on the most pro-business president since Calvin Coolidge.

During the campaign, Democrats pointed out that a massive tax-cut accompanied by a massive rise in military spending could not bring down the interest rate or lead to a balanced budget.

It makes no never-mind to Wall Street about half-rations in school lunches or closed doors at day-care centers. All it sees is the federal government at the head of the line at the borrowing window, which means the continuation of high interest rates. So Wall Street is telling its customers to go on investing in money-market funds and certificates of deposit.

A Solidarity Day marshall on the windswept Mall gave this explanation of Wall Street's mind-set, which is not treachery, as Reagan views it, but simply self-preservation.

A friend on the New York Stock Exchange, who is "ecstatic" about having Reagan in the White House, told him, " . . .When I go on the floor of the Exchange, I'm not voting Reagan's interests, I'm voting my company's."

Reagan's men in the Cabinet and in Congress talk darkly of calling Wall Street on the carpet, hauling it into the Oval Office for a good talking-to.

But what would Reagan tell them--that they must patriotically demand that their customers invest their money in businesses, which are choking on interest rates, and take losses for the Gipper?

The other day in Denver, he chided them for abandoning him: "Wall Street better look to Main Street."

Financial consultants say defensively, "Doesn't he understand that Wall Street is Main Street? We have thousands of small investors. We just reflect them."

Peter G. Peterson, Richard Nixon's secretary of commerce, was one of those few voices from the financial community who warned that tax cuts without cuts in "entitlements"--that is, Social Security and government pension programs--would not add up to a balanced budget. "Blaming Wall Street for what is happening is like blaming the waiter for obesity," he says. "Besides, what possible motive could we have for wrecking the market?"

Wall Street, without really meaning to, is sharpening the horns of Reagan's dilemma--whether to cut the military budget, which is sacred to him, or cut Social Security benefits, whose recipients are sacred to him politically. Since he got scalded on his first outing on Social Security, Wall Street may unwittingly help save some widow's mite.

What he was saying in Denver is that the country is on his side in cutting back social spending.

A Washington Post dispatch from Miami certainly bears him out. Janis Johnson described a Dade County Commission meeting, at which a blind man, whose federally funded ride to work had been cut, was jeered when he asked for local help. Miami is, of course, suffering special strains: a tidal wave of Cuban refugees, a tainted police force, a furious black community. But if its "we're-selfish-and-proud-of-it" spirit is abroad, even in diluted form, Reagan takes up his knife with a light heart.

Wall Street doesn't care about the blind or vindictive voters, only about the tapes that record the buying and selling of stocks and bonds.

But liberals look to it all the same. Wall Street is an inadvertent ally in another of their causes, the anti-nuclear crusade. The Street has been markedly cool towards nuclear investment since Three Mile Island.

When Rep. Edward J. Markey (D-Mass.), leading congressional foe of the nuclear expansion that Ronald Reagan ardently favors, holds hearings on the subject next month, he's not asking the blue-jeaned protesters who hurled themselves on the barricades at Diablo Canyon. He's asked a couple of the boys in pinstripes from Merrill Lynch to come down and explain that there's no future in it.

A bizarre coalition of the "it isn't fair" and the "it doesn't work" seems to be forming against Ronald Reagan. He must be surprised.