The campaign to discredit Loretta Cornelius, acting Director of the Office of Personnel Management, is in high gear.

Cornelius, hardly a flaming liberal, is the target of conservatives who blame her for the decline and fall of Donald Devine. He withdrew his nomination for a second term as OPM director last week, acknowledging that he didn't have the Senate votes to be reconfirmed.

Senate Democrats, who were out to block Devine, said he politicized OPM by appointing "political commissars" to oversee field operations and by campaigning for GOP congressional candidates last year. They also charged that he secretly delegated himself authority to run OPM operations, even after his term expired and he was serving as a temporary aide to Cornelius.

Devine said his Democratic predecessor also engaged in partisan political campaigns and that the delegation of authority, which the General Accounting Office said was improper, was approved by the White House and known to Cornelius.

Cornelius' "crime," in the eyes of Devine supporters, is that she testified under oath that she did not know about the delegation of authority until after Devine became her special assistant and that he asked her to tell the Senate she knew of the arrangement all along.

Earlier this week, Cornelius fired seven OPM employes, all personal assistants to Devine, saying that they aren't needed because Devine is gone. Her opponents say it is the beginning of an anticonservative purge.

Devine's friends say that Cornelius ignored a White House order not to make any personnel changes. At a White House news briefing Wednesday, however, press secretary Larry Speakes said that the White House "has given her no direction on how to run the agency."

But former aides to Devine have told some members of the news media that the president and his top staff are "hopping mad" at Cornelius. The Washington Times quoted an unnamed official yesterday as saying White House personnel chief Robert H. Tuttle has urged President Reagan to fire Cornelius. Tuttle did not return telephone calls. The newspaper quoted another unnamed "senior official" as saying OPM would have a new director in 10 days and Cornelius wouldn't be around much longer.

Small wonder that OPM employes are baffled. Some sidebars on the situation:

* Wednesday evening, a group of OPM executives appointed by Devine had an after-hours party at the agency. One participant said it was "originally intended as a 'wake' for George Nesterczuk [Devine's personal assistant, who was fired by Cornelius].

"Then we heard the news that Cornelius had been called to the White House and was going to be fired, so we decided to stick around for awhile." Although the firing report was false, one participant in the party walked into his office yesterday and announced, "We won" to his bewildered staff.

* Yesterday morning, Devine appeared on the 700 Club, a nationally televised program hosted by Pat Robertson that is carried locally on Channel 20. During the telecast, Devine was praised by Robertson, a popular fundamentalist Christian broadcaster, for doing a good job at OPM. He also described Devine as a victim of the Washington establishment.

* Today is the last on the job for the seven political appointees: four of Devine's "personal" regional representatives, two confidential secretaries and Nesterczuk, who got his termination notice just before 3 p.m. yesterday.

OPM is functioning, but not at top speed, and the White House should settle the issue.