The board of governors of the American Bar Association today voted down a motion to endorse congressional attempts to shield all innocent third parties, including journalists, from searches by federal law enforcement authorities.

The proposal made in support of legislation that would overturn a year-old U.S. Supreme Court decision that upheld a police search of the Stanford Daily, the student newspaper at the California university, now goes to the ABA's policymaking House of Delegates where it is expected to generate considerable debate.

The meeting of the bar's top leaders opened the ABA's 101st annual convention here.

Another media-related question - televised trials - was the subject of brief discussion at the board's morning session. Although the ABA soundly rejected the use of cameras in the courtroom at its meeting last February, one of the highlights of this convention is expected to be a mock appellate hearing in the Dallas County Courthouse on Sunday afternoon, during which leading communications-industry lawyers will argue the question.

Today, however, one board member who wanted to know why the question had resurfaced asked ABA President S. Shepard Tate whether "this is something generated by the television people again."

"Definitely not," Tate said, adding that it was felt that the question simply merited further "exploration." Tate said he wanted to make it "crystal clear" that he was not trying to change the ABA's stand on the issue.

In the Stanford Daily case, the "critical element" in such third-party searches was not whether a property owner is s suspect in connection with a crime under investigation but whether there is "reasonable cause" to believe that sought-after evidence is on the property. The ruling was widely condemned by news organizations who said they feared the decision would lead to widespread abuses by law enforcement authorities.

At today's ABA board meeting, however, member Adrian M. Foley Jr. of Newark, N.J., accused the nation's press of an "absolutely juvenile" overreaction to the Supreme Court case. Another board member, M. Roland Nachman Jr., of Montgomery, Ala., said he had "real questions" about any attempts to "undo by legislation what the Supreme Court has done."

The resolution, disapproved by the board in a 14-to-6 vote, was proposed by the ABA's criminal justice section. Board member William H. Erickson, a justice of the Colorado Supreme Court who spoke for the section, characterized the issue as one of "extreme public importance," bearing directly on the "essence of the right to privacy." He argued unsuccessfully that the resolution was "not a restriction of constitutional rights but an attempt to enhance and guarantee that certain rights exist."

In other action, the board voted not to take a stand on a controversial resolution in favor of allowing sentencing authorities to consider "mitigating circumstances" and other factors before imposing a death penalty for a federal crime.

Two years ago the ABA House of Delegates defeated a resolution urging the states to abolish the death penalty. During lengthy discussions today board members made it clear they did not want to take any action that would provoke the House into debating anew the death penalty.

Erickson, again speaking for the criminal justice section, argued that the proposal was intended only to recommend standards for imposition of the death penalty, but other board members said that any action on such a resolution would imply that the ABA was taking a stand on capital punishment per se. It was clear today, however, that board members felt they would not be able to avoid a penalty debate when the House convenes next week.

This afternoon, the board voted to send back to the criminal justice section recommendations to upgrade the legal status of prison inmates, a process that has been under way for nine years. Former ABA president William B. Spann Jr. called the proposed standards "completely unrealistic" and said their implementation would result in better treatment for prisoners than for the poor and aged. Among the items opposed by board members were consultation with inmates over the content and quality of education programs offered in the nation's prisons, the elimination of dress codes, the setting down of rules on the use of deadly force by prison guards, and the extension of voting privileges to inmates.

About 8,000 lawyers are expected to assemble here, housed in at least 10 different hotels for the ABA convention, most of which is scheduled to take place in the cavernous Dallas Convention Center. The convention, elaborately organized at a cost of about $1 million, will end next Wednesday.