For years he has been a prominent participant in Democratic affairs. His philosophical leanings are definitely liberal. He played key roles in government when the Democrats were in power. He has done all he can to keep the Democratic flag flying when the Democrats are out.
Would he be willing, I asked, to provide a ''balanced assessment'' of the Reagan presidency ''from the Democratic point of view?''
He laughed, recalling a book titled something like ''An Unbiased History of the War Between the States - from the Southern Point of View.'' He agreed to comply with the request but only if there were no attribution.
''First,'' he said, ''let's look at the positive side. Ronald Reagan is the most effective communicator in the presidency since Franklin D. Roosevelt. The size of his base of support is remarkable. Other things being equal, people generally want him to succeed.
''Also, it was Reagan who first picked up on the major issue of the 1980s - the need to create investments and rebuild the basic strength of the economy.
''Additionally, with his Mideast peace plan the President has made an honest attempt to bring about a new initiative there.
''And finally, up until now, this President has been steering away from the practice of some recent presidents of resorting to name calling and snarling. He has done what he could to stay above this sort of thing. Recently there have been some cheap shots from the Republicans in these congressional elections. But there is evidence that Reagan is not personally involved in this.''
The informant began to warm to his assignment. Obviously it was more fun to be a little partisan.
''Now,'' he said, ''let's look at the negatives. First, Reagan is very simplistic. This came through in the way he bought the supply-side theory of Kemp-Roth which triggered all kinds of harmful side effects on the economy.
''He has attempted to do everything at once and to excess. The big Kemp-Roth tax cuts and the military buildup have created such an enormous deficit that for two years the Federal Reserve has found it necessary to keep the economy in a monetary straight-jacket.
''Now the Fed is easing this restraint. But even with this easing by the Fed we still will probably have a deficit of $175 to $200 billion next year - which will send interest rates soaring again.
''The President has squandered an enormous opportunity. He had the good will of people of both parties, including blue-collar workers and many moderate Democrats.
''But what has happened is that he misplayed this popularity - this mandate - and went to wretched excess with Kemp-Roth and military spending.
''Also, the President has done what he didn't need to do - play for the support of the conservative right wing. We've seen this in his support for Secretary Watt's attempt to turn back the environmental clock, his support of school prayer, his support for the tax-exemption status for discriminatory institutions, his support of the constitutional balanced-budget amendment, and more.
''He had an opportunity to spurn the pressure groups and the interest groups. Instead, he has made this effort to appeal to the true believers. And by playing to the gallery the President has, in my opinion, lost his chance of holding and building on the support he came in with.''
What does this Democrat recommend the President do to save his presidency?
A: He should go to Congress and say, ''I'll be willing to take some major reductions in Pentagon spending if you will help me in achieving major cuts in entitlement programs, including social security.''
If he would ask for this partnership in this way it would be most difficult for the Democrats to turn him down - and this could rejuvenate his presidency.
Q: Will Reagan run in 1984?
A: Those around him will probably convince him that it is his duty to run. Further, if there is a visible trend toward a better economy - including lower unemployment - he will beat any of the Democrats who now are talking about running.