The case for Gen. Alexander Haig as secretary of state is that he is authoritative, articulative, well-schooled in the diplomatic arts at the feet of Henry Kissinger, much-admired by Europe's leaders as a consequence of his NATO command, possessed of a broad "strategic sense."

And, what is more, his supporters say, he is the only Reagan Cabinet choice who has proven himself in the "vortex" of high crisis. In the next breath, we are told that it would be a very bad thing for the country if the Senate Foreign Relations Committee, in examining Haig's credentials, starts digging into that particular vortex -- the complex of crimes, improprieties and duplicities known as Watergate.

Well, you can't have it both ways. A Senate review of Haig's credentials is not a criminal investigation. But there is more to senatorial advice and consent than merely passing judgment, up or down, on the president's choice. (Given the latitude a president is entitled to in picking his subordinates, Ronald Reagan is probably entitled to Haig.)

But not the least of the purposes of the confirmation process is that, in the course of taking testimony, a record evolves.

Commitments can be sought, if not always extracted. Philosophy and predilections can be explored. In short, benchmarks can be established, against which the officeholder can be held to future account.

The first benchmark I would want to see established has less to do with Haig's world view than with his constitutional views. Loyalty is often said to be his greatest attribute. So where, in our scheme of things, does he think the loyalty of a government servant lies? To his superiors, unquestioningly, or to the public? To the president as commander-in-chief, or to the president as the elected representative of the people, sworn to uphold the people's rights?

For these questions, Watergate provides the best available test. And what could be more fair than to present as first witness Leon Jaworski, the second Watergate special prosecutor, who is now leading the chorus of Haig supporters? "Herioc" is the way Jaworski now describes Haig's performance in the Watergate ordeal, and I do not question his sincerity.

But in cross-examination, so to speak, I would introduce in evidence Jaworski's own memoirs, published in 1976 -- somewhat closer to the events. In his book, "The Right and the Power," Haig comes across as a devious, heel-clicking sycophant, single-tracked in his defense of the president, and consistently resistant to Jaworski's purposes and judicial processess.

These were not the clouded, critical "final days." Jaworski's chronicle runs back to his first encounter with Haig. He found him "a handsome man . . . articulate and persuasive." But he was not taken in by Haig's silky insistence that Jaworski was not only the "virtually unanimous" choice to succeed Archibald Cox, victim of the infamous Saturday Night Massacre, but also "high on the list for appointments to the Supreme Court."

Jaworski saw that as "bait." But he accepted on faith Haig's explicit commitment that he would have the independence so rudely denied Cox. "You're a great American," Haig told him, adding: "The key words in any news conference are that you've got the right to take the president to court."

"I'll remember," Jaworski recalls replying, and he did. Only a few months later, Jaworski was in court, fighting a White House effort to quash his subpoenas for tapes and other evidence. In a letter to James O. Eastland, chairman of the Senate Judiciary Committee, he declared that the White House position "contravenes the express agreement made with me by Gen. Alexander Haig. . . ."

When Haig later protested that no agreement had been broken by him, Jaworski writes: "I gave him no solace."

Regularly, says Jaworski, Haig "deprecated" the plea-bargaining agreements. He refused to see any criminality on Nixon's part on the famous March 21 tape -- even when confronted with Jaworski's prim, contrary view -- though he did find it "was terrible beyond description."

And so it went: Jaworski battling for the evidence, Haig obstructing him at every step. At one point, Jaworski reports that, seeing "we couldn't be stopped one way, Haig . . . took off his diplomat's hat and put on his Army helmet . . . [saying] 'Things are going to get bloody, Leon.'"

At the very end, Haig said to Jaworski, about the celebrated 18 1/2 minute gap, "I don't mind telling you what I haven't the slightest doubt that the tapes were screwed with." Earlier Haig had laughed off the gap as the work of a "sinister force."

"I'm not trying to save the president, Leon," Haig once said. "I'm trying to save the presidency." When Jaworski replied that "you may be destroying the presidency," Haig "just shrugged his shoulders."

Loyalty? To the president, unswerving. But to the public interest? Judging by the performances of Haig in the Watergate "vortex," that's something the Senate should want to question him about closely. "The Rights and the Power" provides a useful text.