Washington — It looks like a bullish year ahead for President Reagan. Election day is just 12 months away, and each passing week seems to bring one more tidbit of good economic news for the President to savor. The latest report - that the United States jobless rate has fallen to a 20-month low of 8.8 percent - presages even more favorable news, economists say.
It's an old political axiom that the only two things that count on presidential election day are peace and prosperity. While the peace factor appears somewhat tenuous, prosperity is shaping up as a big plus in the equation for the White House.
''We're expecting the kind of year in 1984 that an incumbent president would like to run on,'' says Robert F. Wescott of Wharton Econometric Forecasting Associates.
That sentiment is echoed by other economists. Says James Pihera, assistant director of Georgia State University's forecasting unit: ''The economy next year will be in good shape. The Democrats could have a difficult time making it much of an issue.''
Barry P. Bosworth, who once worked for the Carter administration and is now with the Brookings Institution, observes: ''I think the Democrats will find it increaingly difficult next year to make an economic case. For the broad middle class, the economy is going well.''
Mr. Reagan's No. 1 domestic problem with voters has been unemployment. Despite stimulative fiscal policies, including tax cuts, heavy deficits, and higher defense spending, the number of Americans out of work rose to 12 million a year ago - 10.8 percent of the work force.
But since last December, the job market has rallied swiftly. In 11 months, the number of Americans working has risen by 2,792,000 - the fastest increase since World War II, according to the Bureau of Labor Statistics.
As a result, forecasters say unemployment could be at 8 percent by election day, 1984. In fact, some experts say it could even fall to the 7.5 percent range by that time - right where it was when the Democrats turned the White House over to Reagan in 1981.
What will the rest of the economy be like when voters next go to the polls? Two of the forecasting services with the best records for predictions - Wharton and Georgia State - suggest that there will be very few minuses for Reagan's opponents to exploit.
Wharton forecasters expect encouraging news to keep pouring in on inflation, economic growth, auto sales, housing starts, interest rates, and personal income right through the election season.
While the US economy has expanded rapidly this year, Wharton expects even faster expansion in 1984, with 5.7 percent real growth. Wharton sees a strong year for car sales - about 10.7 million units next year. And housing starts should total about 1.8 million for the second good year in a row. All this should take place against a backdrop of only moderate inflation, Wharton says. This year's rate of about 3 to 3.5 percent may rise to about 5 percent for all of 1984.
Interest rates should be in the range of 11.6 percent for the prime, and 13.8 for home mortgages - approximately where they are now, Wharton says.
Predictions from Georgia State are similar. On election day, voters could go to the polls with inflation at about 6.1 percent, unemployment at about 8 percent, auto sales running at an annual rate of 10.73 million, and the Dow Jones industrial average at 1263.6, well above where the Dow was when Reagan came to office, Georgia State says.
For the Democrats, all this leaves two very big questions about 1984: Can unemployment still be turned into a major political issue? Are there other weaknesses in the economy that they can exploit?
Mr. Bosworth says that with unemployment falling, that issue is rapidly fading for Democrats.
His studies of the issue point to one very important fact: When the unemployment rate is dropping, the political value of that issue to a presidential challenger drops too, even when the rate is still rather high.
The reason for this is quite simple, Bosworth says. When unemployment is rising, there is widespread fear among workers, even those who have relatively secure jobs. That fear drives them to look for new leaders.
But when the jobless rate is falling, that fear begins to vanish and the incumbent looks better. The direction of change, rather than the level of unemployment, is the important thing, he concludes.
Are there other weaknesses the Democrats can exploit?
Top officials at Walter Mondale's campaign say that there are - and they plan to keep the economy at the top of their list of issues, even if the jobless rate continues to drop.
Specifically, a senior aide sees several aspects of the economy that he says worry the public. ''The people are horrified by the $200 billion federal deficits,'' he says. ''There is a public perception that things are out of control.''
The public is also concerned about serious problems in foreign trade, especially the fact that America is buying a lot more from other countries than it is selling to them. The trade deficit could reach $100 billion in 1984, and that shapes up as a major political issue, Mondale aides say.
The public is also troubled by the long-range decline of basic US industries. This is an issue that touches ''national pride,'' and the Mondale campaign plans to hit this hard, advisers say.