WASHINGTON (AP) _ Alexander M. Haig: ''It would serve no useful purpose to put fences around options that would diminish the promulgation of new roadways.''

Haig really said that.

The man who is one of three announced candidate for the 1988 Republican presidential nomination tossed off that gem early on during his tenure as secretary of state when asked whether the United States had ruled out the use of military force in Central America.

Like most diplomats, Haig never spelled out what options he was considering in dealing with difficult situations, but he rarely dismissed such questions with a simple ''No comment,'' preferring instead to engage in rhetorical razzle-dazzle.

The retired Army general and former NATO commander may be a long-shot candidate for president but he seems a sure bet to add linguistic color to the campaign, based on his penchant for mixed metaphors, biting barbs at adversaries and self-deprecating humor.

Haig is not unaware of the commotion he has caused in linguistic circles with his verbal forays.

''It is true that Haig-speak has become a rather notorious form of communication,'' he once said.

As a mixer of metaphors, Haig was a master. To allay concerns about the sale of AWACs aircraft to Saudi Arabia, Haig told the Israelis, ''Keep your powder dry until you see the bottom line.''

To Haig, a politically troubled region was never merely a hotspot but a ''vortex of cruciality'' and a diplomatic hint became a ''nuanceal overtone.'' The word ''caveat,'' once just a noun, became a verb in Haigese: ''I want to caveat that by saying....''

When Haig arrived at the State Department, he called himself the administration's foreign policy ''vicar'' but that goal always eluded him, his designs thwarted by a White House staff which, Haig claimed, constantly undercut him.

Haig was frustrated by these turf fights but often made light of them. He once claimed that he tried to get a head start each day on his enemies by having a bowl of ''Scott's Turf Builder'' for breakfast.

He frequently had breakfast with Defense Secretary Caspar Weinberger but the two never were able to overcome their policy differences. At one point, Haig joked about the intractability of his problems with Weinberger: ''Cap and I had breakfast the other day. There was nobody there but Cap and me and our tasters.''

Sexual innuendo was another favorite Haig device when he was trying to make a point.

Shortly before the administration took office in 1981, Haig drew up a directive to establish the chain of command in President Reagan's foreign policy apparatus.

It was a clear attempt by Haig to stake out a role as Reagan's chief formulator of foreign policy. A colleague recalled that Haig said of the White House at the time, ''We're going to slip off their underwear before they know their pants are unbuckled.''

At a gathering of Washington's football elite in 1981, Haig joked about the large security force which constantly accompanied him:

''The master of ceremonies told me that if Haig and his security detail left the room, it would be half empty. I said, 'If you think that's bad, last night when I leaned over to kiss my wife good night, I had to tell my agent to roll over.'''

In a more serious vein, Haig complained bitterly about what he regarded as the emasculation of U.S. intelligence services under President Carter. During that period, he said, there was a ''conscious castration of America's eyes and ears around the world.''

Haig's decision to run for president came as no surpise to many. His White House adversaries suspected all along that Haig had presidential ambitions. When asked about that possibility a few years ago, Haig borrowed a memorable phrase from former Texas Gov. John Connally to give his answer.

''If you nominate me, I will not run. I you elect me I will not serve. But if you beg me - I might.''

With that response, Haig declined to put a fence around the presidential option and with the announcement of his candidacy recently, he has decided to promulgate a new roadway. So to speak.