When a newspaper critic suggested five years ago that a church-going president like Jimmy Carter should do more for starving refugees from Cambodia, Sen. John C. Danforth (R-Mo.) figured that the same thing could be said of a Republican clergyman-politician from Missouri.

Before long, Danforth, accompanied by two colleagues, was off to visit Cambodian refugee camps in Thailand, returning with chilling firsthand observations that contributed to quick Senate approval of an emergency relief measure.

Then, earlier this year, well before television viewers were stunned by film of famine-stricken Ethiopians, Danforth took off to Africa. This time he went on his own. "After all," he noted with an understanding smile, "it wasn't exactly the Paris air show."

Danforth, 46, returned from Africa with photographs and more poignant reports that helped win both White House and congressional backing for $150 million in food aid for starving sub-Sahara drought victims.

Danforth -- lawyer, Episcopal priest, heir to the Ralston Purina fortune, a patrician figure from the heart of Middle America and the next chairman of the Senate Commerce Committee -- cuts an unusual figure in the Senate.

He is the chamber's only ordained clergyman, a practicing one as well, having graduated simultaneously from the Yale divinity and law schools and continued some priestly functions while practicing law, serving two terms as Missouri attorney general and representing his state in the Senate since 1977.

He makes less a point of his religious orientation than many of his colleagues, however, especially those of a more fundamentalist faith. Although he acknowledges the influence of religion on his political outlook, his is not a Moral Majority kind of linkage of scripture and the ballot box.

When Danforth's religious commitment comes out in legislative debate, which is infrequent, it usually does so in unexpected ways.

For instance, he opposes organized prayer in public schools, saying simply that it leads to "lowest common denominator" worship, making a "mockery" of prayer. He also has opposed abortion and the death penalty with a logic that may satisfy theologians but perplexes those on the left and right fringes of the political realm.

Instead of evangelical zeal and righteous indignation, Danforth brings a calm, reasoned moral force to battles that engage his interest, from hunger abroad to highway safety at home.

This sometimes leads him on what turn out to be naive if noble pursuits, such as the time, five years ago, when he took on an astonished Sen. Russell B. Long (D-La.) in an attempt to tax oil royalties that go to petroleum-producing states like Louisiana. The notion struck Danforth as eminently fair and logical, but Long did not see it that way, and the indignant Louisianian handily trounced him.

Good-natured, easygoing and straightforward to a political fault, Danforth is not one of the Senate's heavy hitters. But he has a reputation for decency and integrity that is warmly acknowledged and respected on both sides of the aisle, leading to expanding influence, if not the kind of raw power that stems from wily manipulation or retribution.

Several Republican senators said, for instance, that his eloquent and high-toned speech nominating Sen. Robert J. Dole (R-Kan.) for Senate majority leader was influential in Dole's election.

"He comes across as goody-two-shoes, and I guess he is," an admiring Republican staff member said.

"He's as close to being a senator of conscience as anyone I've seen around here," an equally admiring Democratic staff member said.

"He's probably held in as high regard for his character as any senator I can think of," said Sen. John H. Chafee (R-R.I.). "He doesn't go in for pettiness in any form . . . . He's really a broad-gauge thinker . . . , a man of tremendous integrity."

If anything, his Democratic colleague from Missouri, Sen. Thomas F. Eagleton, is even more lavish in praise of Danforth. "He's got outstanding personal traits, his word is good to the extreme, he doesn't try to showboat, he's prepared and well versed . . . a thoroughly responsible person," Eagleton said.

But Danforth is not a candidate for political sainthood.

In what turned out to be an unexpectedly tough campaign for reelection two years ago, Danforth resorted to the same kind of negative, personal attack he previously had scorned when it was employed by his opponent, Democrat Harriett Woods.

Danforth's last-minute blitz of negative television ads and slashing stump rhetoric was not as nasty as some of his colleagues' campaigns, before or since, and Danforth appeared uncomfortable on the low road. But he took it, and he won.

He used to enjoy campaigning, he said in a recent interview. Now, he says unhappily, "I think it's just awful."

In Washington, Danforth has been in the thick of battles that are strictly of this world, sometimes involving the kind of compromise that nurtures the political process but provokes scorn from the pulpit.

One of these involves international trade. Representing an import-sensitive state like Missouri, which, among other things, is the nation's second biggest auto producer, took its toll in terms of Danforth's earlier espousal of free-trade practices.

With added clout arising from his previous free-trade credentials, Danforth became the Senate's leading proponent of trade reciprocity, under which the United States can retaliate against its trading partners for refusal to remove barriers against U.S. exports. Key elements of reciprocity were included in the omnibus 1984 trade bill that passed Congress and was signed into law by President Reagan.

Another area is transportation deregulation, where critical segments of his home state's economy, from airlines and aircraft production to railroads and trucking, could suffer from an excess of zeal in getting government out of the marketplace.

Although he is philosophically supportive of deregulation as a reasonably orthodox Republican, Danforth is expected by those familiar with the Commerce Committee to be less predictably pro-deregulation than his predecessor as committee chairman, Sen. Bob Packwood (R-Ore.).

Moreover, the committee he will head is far more interested in filling freight cars than empty stomachs, with a wide-ranging docket covering everything from aging railroads to the burgeoning telecommunications industry, and Danforth appears to relish the prospect of his new job.

Danforth acknowledges that he gets far more satisfaction out of his global hunger work than anything else he has done in the Senate, including his work on transportation issues on Commerce and his even more active role on the powerful Finance Committee, where he is now fourth-ranking among Republicans.

"You work on a trade bill and after a few years you get something that's pretty complicated," Danforth said recently in regard to the omnibus trade bill he steered through the Senate this year as chairman of the Finance subcommittee on trade.

"But when you think in terms of the possibility of playing a part in saving people's lives, that's really something that's very, very fulfilling . . . . Honestly, I think it's the most important thing I've done in the Senate."

Danforth is not averse to the pursuit of worldly power, however, and has plunged into the work of familiarizing himself with every nook and cranny of the Commerce Committee's broad reach.

He inherited the committee chairmanship by virtue of falling dominoes from the Senate Republicans' leadership elections last month. Packwood took the chairmanship of the Finance Committee when Finance Chairman Dole was elected majority leader, opening the way for Danforth to succeed Packwood under the Senate's seniority rules.

For a time, Danforth also was pursuing a mid-level leadership post, the chairmanship of the GOP Policy Committee. But he backed off after it became clear that Sen. William L. Armstrong (R-Colo.) had more votes for the post. "He wanted it, but Jack Danforth has a little trouble with the self-promotion thing," one colleague said.

Although Danforth has a reputation for caution and deliberation, he has become increasingly emboldened to support drastic action on the issue of budget deficits, which he says can be dealt with only by "big, bold measures."

At a time when nearly everyone else in Congress shies away from any suggestion of tax increases, Danforth says without so much as a blink that "we're going to have to raise tax revenues."

On the issue of Treasury Secretary Donald T. Regan's proposal for overhauling the tax code, Danforth said: "If you think you're going to have tax simplification that's revenue-neutral, forget it. We're not going to do it. But if you want to talk about tax simplification as part of a general program that's trying to reduce the deficit and create greater equity, then we can do something."

As for the global hunger problem, Danforth said he intends to continue pushing for emergency relief, along with incentives to help recipient countries strengthen their food-producing capacity. But he is not hopeful about the prospects.

"When there's an immediate crisis and people turn on the television and see starving babies, there's a terrific outpouring of response. Right now the response level is high," he said.

"But in a month or two, the pictures that come back will have people in camps, they will be surviving, children will be active and playing again. The photo opportunities will not be as dramatic. It will just be long-term hopelessness. Where do they go next? They will have been there five years. That's going to be very, very difficult."