The report by Roman Catholic bishops on economic conditions of the poor has set off a caterwauling among otherwise thoughtful observers that is dismaying if not disheartening.

From the left, voices such as The Boston Globe have criticized the bishops for bad timing. While supportive of the bishops' goals, liberal commentators say the report should have come out before the election when presumably it would have provided good ammunition against President Reagan.

On the right, the editorial writers of The Wall Street Journal and columnists such as William F. Buckley Jr. and George F. Will have attacked the bishops for bad judgment. In their view, the bishops are trying to insert both themselves and the government too deeply into the workings of free enterprise. Moreover, many of the bishops' solutions to poverty -- more money, more Big Brother -- are the antiquated answers of the past that have only created a cycle of dependency.

Well, as Reagan likes to say, forgive me, but these criticisms strike me as beside the point.

If anything, the bishops have spoken up at exactly the right time and in the right way: at a moment when the nation is about to make crucial economic decisions, the bishops have said we must focus once again on the rising tide of poverty in America.

On the very day the bishops published the draft of their pastoral letter, the president's budget director, David Stockman, revealed to other key players in the administration a disturbing picture of future deficits. To most economists, it is clear that we must soon act decisively or we will be sucked into the trough of another recession.

Enter the bishops. They have said in effect that in our zeal to curb spending, we are morally obliged to remember the poor. The bishops do not pretend to be experts on remedies, and some of the ones proposed in their letter have unfortunately failed in earlier years. But surely their call for new attention to the spiritual and economic deprivation of a growing number of Americans should be welcomed.

In 1977, according to federal statistics, about 25 million people lived below the poverty line in the United States; that number rose nearly 7 million by 1981 and another 3.5 million by 1983, reaching a level nearly as high as in the early 1960s when a book by Michael Harrington startled the nation and its president, John F. Kennedy, into action.

There are legitimate arguments about measurements of poverty. But there is no blinking aside the fact that class differences are sharply growing. Between 1980 and 1984, reports the Urban Institute, real disposable income -- what's left after inflation -- rose by nearly 9 percent for those in the top fifth of the population while dropping by nearly 8 percent for those in the bottom fifth. The bishops' pastoral letter also points out that the richest 20 percent of the population increased its share of national income from 41.5 percent in 1977 to 49 percent in 1982. By that time, the "richest 20 percent of Americans received more income than the bottom 70 percent combined. . . ."

Those who attack poverty programs often say we should never redistribute income in America. But that's exactly what we're doing now -- except it's flowing the other way.

Two measures are needed:

First, just as the White House has declared defense spending out of bounds in its budget cutting, we need to declare the poor out of bounds. They should be spared from the next round of budget cuts. Those who are most destitute have been protected in the past; their safety net is intact. But in too many cases, the working poor have not been protected.

This time, we must finally turn to the middle class benefits that have been largely unscathed in past budget cuts. (The bishops point out that, for the middle class, we like to call benefits "entitlements," while for the poor, they're "handouts.") Pensions, Social Security, Medicare, tax shelters -- they are now ripe for consideration. Those of us who are better off must either decide to cut back on some of our "entitlements" or begin paying for them through higher taxes.

Second, we need a fresh dialogue on better ways to stop this rising spiral of poverty. The administration needs to invest more effort and imagination, and Congress ought to at least go along with Reagan's call for urban enterprise zones.

But more than that, public opinion leaders need to return to the subject. One of the best responses is contained in a lay letter that a group of Catholic leaders, chaired by former Treasury Secretary William Simon and theologian Michael Novak, published a week before the bishops spoke out. Their report is a spirited defense of capitalism that is both sympathetic and constructive toward the poor, more than can be said for many other critiques.

The country will not solve the plight of the poor by more benign neglect. In their letter, the bishops have once again stirred our conscience, and for that alone, they have performed a service.