Perhaps President Reagan and his chief economic adviser, Murray Weidenbaum, are not in communication with each other. For Weidenbaum, in a statement to Congress last Wednesday entitled "Is Reaganomics Working?," said:

"To begin with, I do not 'blame' Federal Reserve policy in 1981-82 for the current recession." He added that the Fed's shift to a policy of forcing reduced growth of the money supply "was precisely the policy which we urged" at the beginning of the administration.

But this reporter knows from an unimpeachable source that in the course of a dialogue during the first plenary session at the Versailles summit, President Reagan said flatly that the Federal Reserve "has brought on the recession."

Reagan's observation was triggered by an expression of concern by Canadian Prime Minister Pierre Trudeau, who warned about the dangers inherent in a high interest rate policy. Trudeau referred to the current economic malaise as a "catastrophe" for both the rich nations at Versailles and the poor ones not represented.

It was at that point that Reagan laid the blame on the Fed, later adding in an exchange with West German Chancellor Helmut Schmidt, who complained about weekly issuance of the money supply figures, that "we can't order the Fed around."

Back home after the summit, Treasury Secretary Donald T. Regan passed up an opportunity--at a breakfast with reporters--to give a vote of confidence to Federal Reserve Chairman Paul A. Volcker, saying only that "his policies are the correct ones, but their carrying out leaves something to be desired." Regan trotted out the old administration complaint that "there are too many spikes in the money supply that have to be taken out," a reference to what the Reagan administration believes is a defective day-to-day performance by Volcker and his associates.

Behind this renewed internecine warfare between the White House and the Fed is the reluctant admission by the administration that whatever happens to the budget on Capitol Hill, there will at best be an anemic economic recovery because of high interest rates. And in this circumstance, the Fed makes a convenient scapegoat.

The administration has been forced to admit that whatever recovery ensues this year will be led by a revival of consumer spending, and not by the surge of capital spending that it had forecast last year in the glory days of "supply-side economics" and the miracles it would generate.

Instead of adding to their plans for expanding plant capacity, businessmen are cutting them back sharply, according to new figures issued by the Commerce Department last week. In real terms, business now plans to invest 2.4 percent less this year than last, a sharp reversal from what they said they were planning just at the start of the year.

Data Resources Inc./McGraw Hill, a respected private consulting firm, is even gloomier, forecasting a 6.4 percent decline this year, with the result that the share of real GNP devoted to business fixed investment will continue to slip, and is not likely to return to the level of three years ago until the mid-l980s.

Why is such a decline in investment occurring, DRI asks? The answer is relatively simple: the interest rate-induced recession and high unemployment provide no incentive for expansion. Poor earnings and threatened bankruptcies, coupled with the inability of the auto and steel industries to compete with imports, combine to make the outlook grim, the research group says.

Weidenbaum argues that it is only normal for investment outlays to "constitute the second stage of recovery, following the expansion of consumer purchases." But he is also candid enough, given the misplaced optimism of last year, to say that it all depends on getting interest rates down "much further," and that even so, "it is hard to envision a boom in investment in the short run."

The difference between the Reagan/Regan and Weidenbaum messages is that while all blame the recession on high interest rates, Reagan/Regan lay the blame for high interest rates on the Fed. Weidenbaum says "we have not a truly satisfying account of why interest rates have remained so high."

Most outside observers think that "a truly satisfying account" is not difficult to find: interest rates have soared to record levels because the administration pursued a recklessly inflationary fiscal policy under the guise of "supply-side" economics, and has showed itself to be utterly incompetent to judge the impact of its policies on the financial markets.

As DRI's Otto Eckstein has observed, "the financial markets can expect little but disturbing news about the budget for the next six months, and there is no realistic prospect that the deficits will drop below $100 billion annually over the next several years even if a compromise is reached."

The administration is now suffering, world-wide, from a credibility gap as serious as the one that caught up with Jimmy Carter and ultimately led to his downfall. Even if Congress adopts a budget, there will be few who will believe the numbers in it. Business and the public lack confidence in both the White House and Congress, and for good reasons.