Not long ago, an old friend privately approached John Ehrlichman and asked him whether his novel, "The Company," was intended to be a true story about the CIA and the White House.

"Maybe," smiled Ehrlichman, and he jauntly dismissed both question and questioner without another word. The story has remained in that haze ever since.

In dramatizing the novel for television, however, ANC has stripped away almost all such ambiguity. While sticking to the basic outlines of the Ehrlichman story, the script writers have incorporated such vast quantities of other Washington folklore that they leave little doubt of their intentions: They want you to believe that this is the way the game is played.

It is hard not to fall for the bait. When the opening minutes show President Esker Anderson (alias Lyndon Johnson) talking to official visitors through the bathroom door, one recalls countless tales about Johnson's peculiar conversational habits. When President Richard Monckton (Nixon) puts on a mask for television cameras or seethes about the press, there is instant recognition. And when Frank Flaherty (the fictionalized equivalent of Haldeman) lashes out at obsequious underlings, there are immediate chills from the old days when an "HRH" memo would paralyze you with fear.

The material is convincing, then, much more so than Ehrlichman's novel. But that is all the more reason to be on guard. Just because the TV series is more credible than the novel does not make it more true - only more dangerous.

Make no mistake: The television series is cracking good entertainment. ABC deserves ample credit.I sat spellbound during the first two episodes (except for the soggy romantic interludes) and eagerly took forward to the rest.

Yet there is something terribly troublesome about the power of the networks to weave together tangled strands of reality with large pieces of fantasy and then to sell the lot as "fictionalized history." People already have enough trouble distinguishing the real from the phony in Washington, and when the fictional gauze is as thin as it is here, they are apt to believe the whole story. Both people and institutions could suffer in the process.

In some cases, the damage will not be large. It is difficult to believe that yet another portrait of Richard Nixon as a lonely, compulsive, vindictive man will drive his esteem any lower. The country has already made up its mind about Nixon, so that this series will make no more difference than would a hundred former members of his staff swearing on his mother's Bible that the Nixon they knew the Nixon of the second Frost interview on foreign policy, for example - was a very different man.

Other portraits, however, will inflict greater personal loss. "Haldeman" emerges here as ruthless and arrogant, the man who blockaded the President in his office, and he could be all of these, but he also had redeeming features: He was totally dedicated to serving what he believed to be the best interests of his country, he was honest of blunt, and the efficiency that he brought to the White House often contributed significantly to the process of public policymaking.

Richard Helms could lodge even stronger protests. This series depicts a CIA chief as a sensitive but self-serving director of the CIA, willing to lie, blackmail or even murder to advance his own interest or that of "the company." I do not know Helms well, but those who have served with him portray his as much less devious, less conniving, more honest, and much, much more bureaucratic.

The fictionalized account of the Helms' directorship points up, in fact, the larger danger from this series.

The public mytholog created here is that the CIA engaged in counter-intelligence against the Nixon White House and when CIA operatives caught White House plumbers wire-tapping a Washington journalist, the fictional CIA chief used that evidence to blackmail Nixon.

It makes a wonderful tale of skull-duggery, fortifying one's worst fears about the CIA, but where is the proff? No one has ever produced it. Many have been called to try, but no one has been chosen to succeed.

The story suggests that as part of his blackmail price, that chief asked to be transferred from the CIA to a plush foreign ambassadorship. Until contrary facts can be brought forward, the record suggests that Helms was fired by Nixon because the CIA wouldn't fully cooperate with White House leaders such as Ehrlichman during the early days of Watergate.

For the CIA, the difference between the two accounts is substantial. One can be a tonic, the other a poison. With the CIA already in trouble with the public and with Helms already under a cloud for an entirely separate matter relating to Chile, the fact that ABC has chosen the uglier version will only make it that much more difficult to restore public trust in the intelligence community.

This series also poses such difficulties on a higher plane. The network did not change the name of the work from "The Company" to "Washington, Behind Closed Doors" for idle reasons. The message for Peroria, as Ehrlichman would say, is that everyone here plays the game the same way: mean, fast, and cutthroat.

Washihingtonians usually know better. They know that people play political hardball here, but they also know that no more representative of the overall city than are the Georgetown salons. But when leading network and friends such as The New Republic are both jumping on Washington, as they have done recently, it's time for the entire establishment to take another look at its public pereption.

As long as Ehrlichman's tale was confined to the pages of his novel, it seemed diverting but harmless. To be sure, it conveniently explained his own role in early Watergate days (an innocent third party), pinned the blame on Nixon and Chuck Colson, and pulled the CIA into the thick of the plot. But still, it was only one more version of Watergate from an interested party.

By dramatizing the novel so appealingly, however, ABC has in effect placed a more credible seal of authority upon its contents and has greatly magnified its public impact. Washingtonians are likely to prove the most attentive audience in the country, but they ought to be the first to urge great caution upon other viewers.