The prospect that economically hard-pressed voters of Oregon's sprawling Second Congressional District will return Rep. Al Ullman to his powerful tax-writing post in Washington after scaring the life out of him symbolizes the great lost Republican opportunity of 1980.

Ullman, chairman of the House Ways and Means Committee, had offended his constituents not only by inattention but by intimate association with the hated federal leviathan. But aggressive Republican challenger Denny Smith offers no alternative vision. That makes it likely Ullman will squeak into a 13th term in Congress through campaign appearances at sparsely settled crossroads towns in expiation of past absences.

Smith, a decorated Vietnam jet pilot and son of the late Gov. Elmo Smith, is making a puckly first attempt at elective office by challenging the previously impregnable Ullman. Nevertheless, he suffers from the Republican disease: negativism that has contributed to a half-century of political defeat. While giving losts of reasons to vote against Al Ullman, he lacks a compelling argument to vote for Denny Smith. Substitute the names Carter and Reagan, and the analogy to the presidential race is evident.

Put more tactfully, that was the message Rep. Jack Kemp of New York brought here in a campaign trip for Smith. At a reception for the party elite prior to a fund-raising luncheon in Portland, Smith's television spots ridiculing Ullman were shown to laughing, applauding Republicans. Kemp neither laughed nor applauded. "I'd like to hear something about Denny Smith," he muttered.

Kemp privately urged Smith to take a positive approach, and then showed Smith what he meant in his luncheon stem-winder. He demanded "incentives for the working men and women of the country" and insisted that "we can have full employment and economic growth without inflation." His familiar formula: fthe Kemp-Roth tax reduction bill.

Assembled Republicans cheered Kemp's rhetoric but did not buy his program.

"This is not a tax-cut state," one party leader informed us. "I don't think you'll find Denny or the other congressional candidates stressing it." Actually, Smith does talk about a 10 percent tax cut in nearly every speech, but it is not the campaign focus. Nor does Smith relate tax cuts to incentive, growth and jobs.

That seems a major mistake. It was Ullman's ill-conceived advocacy of a national value-added tax (since repudiated) that got him in trouble here. His record as Ways and Means chairman shows consistant opposition to tax reduction. What's more, his financially depressed constituents east of the Cascades are not nearly so anti-tax cut as Portland's Republican elite imagine.

At the Mt. Vernon Grange Hall a few miles from John Day, the 16 voters there to hear Ullman were bowed down by ravages of federal taxation. One 40-year-old carpenter told us he managed to earn $20,000 last year only to discover on April 15 that he owed Uncle Sam $4,000 more in taxes. "For the first time, I ask myself: Why work? What's the use?" he said.

Questions directed at Ullman were a litany against the big, bad federal government. Although Ullman's record is decisively more liberal than conservative (ratings of 63 percent liberal last year to 3 percent conservative), he commiserated with them in his friendly, painfully inarticulate fashion.

But whereas Jack Kemp Promises growth, Al Ullman preaches austerity. Campaigning in a lumber and timber area wracked by unemploment, he declared: "we ought to have a slow recovery." He promised some kind of 1981 tax cut but suggested it be limited to stimulating investment: "We've got to get people to save money instead of spending it."

That brought a frown and a question from one woman: if nobody spends, how can we have prosperity? Ullman did not quite answer her. But she and the others present at the Grange hall are voting for Ullman. That includes many (including the disheartened $20,000-a-year carpenter) who support Ronald Reagan.

Answering our questions, these and other voters we met in the John Day area could name nothing Smith stands for -- certainly not tax reduction -- except attacking Ullman and maybe disrupting the Social Security system. Right-wing Republicans, resembling moths who cannot resist the flame, persist in tinkering with social Security. Like Reagan, Smith has disavowed any desire to make the system voluntary; like President Carter, Ullman ignores the disavowal. It is, in fact, the centerpiece of Ullman's campaign.

"I think people around here just wanted to scare the pants off Al for ignoring us," a John Day Businessman predicted. Ullman's lack of an Oregon home is Smith's favorite TV spot. That this and other Republican challenges, including Reagan's, do not lock in on deeper discontent may save the chairman of the Ways and Means Committee as well as lesser Democrats Nov. 4.