Sen. Frank Church (D-Idaho), in line to become chairman of the Senate Foreign Relations Committee, is eager to restore the committee's power and prestige in the 96th Congress.

If Church's intentions are fulfilled, a smaller and more competent committee staff under new leadership will help the chairman and new ranking Republican, Jacob K. Javits (R.N.Y.) make the committee once again a force to be reckoned with by the executive branch.

At the same time, because of an influx of new conservation Republican members, the Foreign Relations Committee is likely to become a more contentious forum, and thus more representative of the Senate.

The combination of new leadership and half a dozen new members seems certain to bring an abrupt end to the relative somnolence of the last four years, when the committee has been led by the aged (and now retiring) John J. Sparkman (D-Ala.)

Whether the committee can be restored to a preeminent position in the policymaking process in Washington is problematical. But associates say Church-who ran for president in 1976, and could do so again-has the ambition to try to make the committee once more truly important.

Though he won't formally assume the chairmanship until late January, when Senate Democrats are expected to ratify his ascension, Church has moved quickly to give the committee his own imprint. He has already chosen William Bader, a Pentagon official, to be the new staff director, and Bader has begun to recruit new staff members-though he, too, will not be formally appointed until later this month.

Current committee staff members have reacted uneasily to reports that their ranks will be depleted, and then renewed with new appointees. "The quality [of the staff] has become uneven," Church said in an interview.

Church and Bader have set out first to recruit experts who can help the committee conduct thorough hearings on the strategic arms limitation treaty (SALT) agreement expected to come before the Senate later in the year.

The two are known to feel that a reconstitued Foreign Relations Committee will win or lose the respect of the Senate on the basis of its handling of the SALT II pacts, which could provide one of the more dramatic Senate fights in many years.

It was widely believed in the Senate that the Armed Services Committee held better hearings on the SALT J agreements in 1972 than did Foreign Relations.

Apart from its new leadership, the committee is likely to be substantially altered by new members, particularly on the Republican side.

According to sources in the Republican leadership, the men most likely to be new GOP members are Jesse A. Helms (N.C.), S. I. Hayakawa (Calif.), Richard S. Schweiker (Pa.) and Richard S. Schweiker (Pa.) and Richard G. Lugar (Ind.). All four are to the right of the moderates who have traditionally filled the Republican places on the panel.

Their presence will enliven committee proceedings, and may also set off a fight over allocation of staff resources. Traditionally, the committee staff has been considered nonpartisan, and has worked jointly for both Republican and Democratic members.

Sen. Howard H. Baker Jr. (R-Tenn.), the minority leader and a committee member, is said by aides to favor dividing the staff between the majority and minority, as is the practice on other Senate committees. Javits and the second-ranking Republican, Charles H. Percy (Ill.), are not eager to split the staff, aides say, but if a majority of the Republicans request such a division, the Senate's rules provide that this would have to be done.

Such a split of the committee staff would be symbolic evidence that the era of "bipartisan foreign policy" has effectively come to an end, which seems to be the case.

Even without the creation of a minority staff on the committee, the new Republican members will give its deliberations a more realistic tone. Last year the committee approved the Panamal Canal Treaties by votes of 15-to-1, an indication of its internationalist bias as well as its unrepresentativeness of the full Senate (which was divided 2 to 1 on the treaties).

"It's probably healthy" for the committee to include a bloc of conservatives, one staff member said last week.

Without such internal opposition, the committee can get lazy and sloppy, this aide added.

There will also be two new Democratic members on the panel. One seems certain to be Edmund S. Muskie (D-Maine), a former member who has decided he would like to rejoin in the new Congress.

Newly elected Sen. Paul Tsongas (D-Mass.) is anxious to join, and to take over defeated Sen. Dick Clark's (D-Iowa) African affairs subcommittee. But a more senior member, George McGovern (D-S.D.), is expected to take that assignment.

Church said he hoped the committee could establish a role for itself as a forum for long-range policy planing and analysis.

For example, he said he would like to hold thorough hearings and report to the Senate on issues like the future of U.S.-Mexican relations, or what policy the United States should follow in Indochina and other parts of South-east Asia, or how more Mideast nations could be brought into the peace process begun by Israel and Egypt.

Church said he might pick one of those topics for hearings to be held later in 1979.

"I see the committee as a special forum in which foreign policy questions can be thoroughly explored," Church said, but quickly added this disclaimer: "I recognize that the president is the chief architect of American foreign policy and that we ought not to occupy our time second-guessing the president on every decision he makes."

On the other hand, when the committee disagrees with the president, "we are obliged to speak out," and "from time to time that is going to happen."

Church said he intends to abolish several existing subcommittees, taking all legislative duties to the full committee level. This was the way Foreign Relations used to operate, and Church said he wanted all members to be able to participate in the legislative process again.

In recent years subcommittees handling the foreign aid and related legislation that comes through Foreign Relations have added numerous riders and provisions to the bills, "junking them up a lot," in the words of one staff member. "The full committee won't approve all the stuff the sub-committees did," said another.

While some members of the committee staff worry about their jobs, others seem excited at the prospect of a revived committee under Church. One of the latter said he thought the committee's place in Washingtonhs scheme of things would change, thanks to Church.

"We'll see more of The Washington Post's reporters because Church is chairman," he predicted "We'll see more of Marvin Kalb, too." Kalb is the diplomatic correspondent of CBS News. CAPTION:

Picture, Church, in line to become chairman, is eager to restore panel's prestige, power. By James K. W. Atherton-The Washington Post