President Reagan is publicly standing by his nomination of Edwin Meese III to be attorney general of the United States. But in the wake of embarrassing disclosures in the Senate Judiciary Committee, he may find that his close counselor is becoming a political liability.
Initially the Meese hearings were expected to be finished quickly, despite the concern of civil libertarians and liberal Democrats about the appointment. That has not proved to be the case. Sen. Howard M. Metzenbaum (D) of Ohio has doggedly pursued a probe of Meese's financial dealings and brought to light findings that raise serious questions about Meese's qualifications to be the nation's chief law-enforcement officer.
Some observers believe that the Democrats initially were less interested in blocking Meese's appointment as attorney general than in making sure he would not be appointed to the Supreme Court if President Reagan won a second term.
Mr. Reagan could have an opportunity to name two or three justices, and Meese has been mentioned as a possible nominee. Given Meese's strong conservatism, liberals would vigorously oppose such an appointment.
Now, even Republican members are concerned that the committee fully air the questions raised before confirming Meese as attorney general.
The latest disclosure in the Senate committee was that Meese failed to mention an interest-free loan of $15,000 to his wife in 1981 by a friend who was later named to a federal post; also that he failed to disclose in his 1982 financial statement the stock purchase for which he said the loan was used, as required by the Ethics in Government Act.
Meese said the failure to disclose the loan was ''inadvertent,'' and he apologized to the committee.
''The Republicans thought this would all sail through, and even most of the Democrats expected Meese to be confirmed,'' a congressional aide says. ''But now both sides are concerned that the committee be seen doing its job.''
Mr. Meese has agreed to appear before the committee again next next week. Committee members also want to explore the matter with White House witnesses.
Election politics have tended to overshadow the Meese hearings. But political experts say they believe that as news media attention intensifies, the public will begin to take notice. This could have political repercussions on the Reagan reelection campaign.
''It's not just a question of possible wrongdoing,'' comments one analyst. ''Meese's dealings point to a double standard and the issue of equity - that people in the higher brackets are trying to bend the rules and procedures.''
''There's a genuine feeling that the attorney general ought to be the attorney general for all Americans, not just for the rich and powerful,'' comments another expert. ''This is an even more sensitive post than interior secretary or EPA director.''
Before the Judiciary Committee began its investigation, Meese was widely regarded as an able individual who, despite decidedly conservative views and charges of insensitivity on social issues, would have no basic problem running the gauntlet of Senate confirmation.
But questions now are being asked about whether the President's White House counselor has a broad enough conception of the public interest to be attorney general and whether his financial dealings and other matters are not ethically questionable enough, if not unlawful, to disqualify him for the job.
Among the things that have come to light concerning Meese's financial affairs and 1980 campaign role:
* Meese received two loans totaling $60,000 from his tax accountant, who later was appointed to the United States Postal Service board.
* A bank that made loans of more than $400,000 to Meese took no action when Meese lagged as many as 15 months behind in his payments, and it even advanced him more money so he could catch up with his loan payments.
After the loans were paid back, the bank chairman was named an alternate United States delegate to the United Nations, and another bank officer was named chairman of the Federal Home Loan Bank Board. A friend who sold Meese's California house and took a financial loss on it became deputy secretary of the interior.
* According to memos released by Senator Metzenbaum, Meese was given information about President Carter's campaign strategy.
Attached to one memo about Carter's plan for rural voters was a cover note from a Reagan aide telling Meese that then-campaign chairman William Casey wanted his views on how to counter the Carter strategy.
Meese said in an affidavit to a House committee that he could not recall receiving such Reagan campaign memos and did not know their source.
Meese has denied any relationship between his financial arrangements and the federal appointments. But some observers saythey believe that Meese's actions may have violated conflict-of-interest laws.
In committee questioning, for instance, Meese's tax accountant, who had arranged loans for Meese, said he had raised the subject of a long-term appointment to the US Postal Service with Meese and White House aide Michael Deaver. He also said Meese had not paid interest or principal on his loans for more than two years.