President Reagan, take heart! Despite your sharp dips in public opinion polls , the American people still like you and believe you are ''trying hard.'' Your bid for reelection (if you so choose) may not be so difficult - the Democrats don't seem to have a consensus ''centrist'' candidate on the horizon. And even if your party drops some congressional seats in November, there's little reason to despair that the Reagan mystique is out the window.
These words of encouragement for the man in the Oval Office come from an unlikely source - Hamilton Jordan, former chief of staff for the Carter White House.
The diminutive and articulate Mr. Jordan has left a Georgia roost in academia to stomp the country for his new book, ''Crisis: The Last Year of the Carter Presidency'' (a review of the book appears on Page B3). His former boss, Jimmy Carter, is due out on the hustings later this fall to promote his forthcoming volume, ''Keeping Faith.''
In his book and during interviews, Jordan says the same thing that Jimmy Carter is almost sure to say later on: The Democrats were evicted from the White House in 1980 because of the hostage crisis, the primary challenge by Sen. Edward M. Kennedy (D) of Massachusetts, and rising inflation. But Jordan says he also blames the loss on a failed political philosophy, flagging partisan support for political parties, and the emerging role of television as a dominant force in American campaigns.
''What happened to us was we tried to carry the party in a different direction,'' explains Jordan. ''The Republicans in Congress were against us simply because President Carter was a Democrat. The liberal Democrats were against us because Carter was abandoning the traditional approach and it left us straddling the middle under attack from both sides.
''President Carter went to Washington without a unified political philosophy that had been affirmed through the election. As a result we kind of played into the special-interest dynamics of Washington. One day we'd be working with liberal Democrats and moderate Republicans trying to kill the B-1. The next day we'd be working with Republicans and conservative Southern Democrats trying to reduce the federal budget.
''So our lack of philosophy . . . denied us having a consensus with which to govern over the four years.''
On party dynamics, Jordan says: ''The party is so fragmented and the country is so awash with special-interest groups that they are pulling and tugging at our political system.
''Parties used to mean something. In this country 20 or 30 years ago if you lived in Bob Wagner's New York City or Richard Daley's Chicago (and) you had a problem, the party would help you. If you had a child that was sick, or an uncle or a cousin that needed a job, and you voted Democratic, you could go to the precinct captain and he could help you.
''Parties used to help people. They used to educate the voters and they used to stand for something. If you were a Democrat, it meant certain things. If you were a Republican, it meant certain other things.''
Singling out television as a prime culprit in loosening party fabric, the ex-White House aide says: ''Largely because of the evolution of television, the clear differences that used to exist between Democrats and Republicans have been obscured. So these Republicans who can sound like Democrats can win an election. And Democrats who can sound like Republicans can win an election. And you don't have any party discipline in the parties or in Congress.
''Television has obscured the historic differences between what the parties stand for and what they do.''
What would the Carter administration do differently if it got another chance?
Jordan indicates that the former president would follow his ''instincts'' more on the economy, try to shake a ''reactive'' posture on inflation, and avoid ''compartmentalizing'' the presidency so much.
''On the economy, Carter (often) didn't follow his instincts. Because it was so imprecise, it was difficult for him to focus on it and absorb it. He was accustomed to say: 'All right. If I do XYZ, I'll have these consequences.' And here he'd be presented all these economic options and make decisions. Six months later, Charlie Shultz would come in and say: Well, you know, this didn't happen and that didn't happen. And Carter would say 'Why?'
''All these variables . . . frustrated Carter. As a result - of the imprecise nature of economic policy decisionmaking - he oftentimes didn't follow his instincts. We often compromised out what his different advisers were telling him. That was the basic mistake we made on the economy.''
(On ''reactive'' policy) ''When I think about the four years we were in office, it was a reaction - we were always in a reactive posture to a single thing and that was the increase in the price of oil. When Jimmy Carter was elected president, the price of a barrel of oil on the world market was $8. When we left office, it was $35. Our whole four years were spent in reacting to all of the impact of that enormous increase in prices on the American economy.
''Certainly we didn't focus on inflation early enough. And we just had some bad luck.''
(On ''compartmentalization'') ''We tended to compartmentalize his (Carter's) presidency too much. He learned, we all learned, better how to do it after we had been there a year or two. People said: Well, if you had taken a different approach to Congress or dealt with the establishment in Washington differently, that would have made a great difference.
''The rub with the political establishment in Washington was first that Carter was not a product of that political establishment, and second, that he was trying to carry the party in a different direction. Throwing all these other things aside, that was the basic problem that Carter had with Washington and the Democratic leadership in Congress, that he was trying to take the party in a different direction. They were coming along kicking and screaming and begrudgingly.''
Who or what can unify the Democratic Party and put it back on the winning track this year and in 1984?
Jordan is reluctant to single out personalities and presidential potentials. However, he says that the present lead in the polls held by Senator Kennedy could dwindle when Democrats ''take a good look at him and decide whether they really want him to be president.'' He believes Kennedy has an ''image'' problem. (In a speech before college students in Georgia, Carter recently scored Kennedy for dividing the party in 1980 and left doubts whether he (Carter) could support him if he got the Democratic nomination in two years.)
Jordan indicates his personal support for former Vice-President Walter Mondale with whom he had a warm relationship in the White House. He also talks about the attractiveness of Sen. John Glenn (D) of Ohio. But he is aware of the liabilities of both these men as presidential candidates.
Again, the recent White House chief of staff insists that only a ''centrist'' Democrat is likely to wrest the White House away from President Reagan and Republicans.
''If I could bet $100 right now about '85, I'd say that Ronald Reagan could very likely be sitting there. I'm not optimistic that we will pull ourselves together, come up with a centrist candidate, come up with his idea and sell it, '' he says.
''What I'm arguing for is a nonideological approach to our country's problems at a time when it seems that the heart and soul of both parties is captured by ideologies of the left and right. I'm maybe wishing for something that's not there.''
This story is based on an interview with Mr. Jordan by editors of the Monitor in Boston, as well as a breakfast meeting with reporters in Washington hosted by the Monitor's bureau chief, Godfrey Sperling Jr.