In the Soviet Union, every candidate for the parliament is a front-runner

For a man in the heat of an election campaign, Valery Saikin looks decidedly relaxed. He has the distinctive poise and self-assuredness of a front-runner as he fields questions from the press and makes a few promises about what he'll do once he takes office.

Such self-confidence is somewhat understandable, since he is the only candidate in the race and his election is virtually guaranteed. What's more, he won't have any campaign debts - the government pays for those.

The fact that he is a known communist won't hurt him in the least. After all, the Communist Party is the only legal political party in his country. And if the recent historical pattern is followed, Saikin will probably get a voter turnout around 99.9 percent on Sunday.

Those in the middle of the American election campaign - the candidates with numbed hands and the voters with numbed eardrums - might not recognize it, but the USSR is also in the midst of a campaign. The contrast with the one in America couldn't be more drastic.

Saikin, head of the Zil automotive enterprise here - which makes, among other products, the limousines that whisk Communist Party power brokers through traffic - is one of some 1,500 people ''running'' for a seat in the Supreme Soviet, nominally this country's parliament.

The word ''running'' is put in quotation marks because there is, in fact, no contest. The results are known before the voters go to the polls. And the word ''nominally'' is used because, although officially the highest legislative authority in the Soviet Union, the Supreme Soviet does little more than give unanimous and unwavering approval to decisions made by the Communist Party leadership.

Despite this, Soviet officials bristle at the suggestion that their elections are inferior to those in Western democracies.

On the contrary, says one official, ''We believe this system is more logical.''

How's that?

''We think the possibility of making a wrong choice is reduced because we make the choice before the election,'' he says.

Primaries and caucuses are unfamiliar to the average Russian. A bit of background is clearly in order.

Once every five years, the Soviet Union holds nationwide elections for the Supreme Soviet. There are 1,500 seats in this bicameral legislature, 750 each in the Soviet of the Union and the Soviet of Nationalities. Each representative is called a ''deputy.''

Deputies in the Soviet of Nationalities are chosen to represent the diverse republics and other governmental units that make up the Union of Soviet Socialist Republics. Thus, when the Supreme Soviet convenes in Moscow's Palace of Congresses, Armenians, living near Greece, are mingling with Yakuts from eastern Siberia. This country, after all, covers one-sixth of the world's land area.

The other half of the legislature - the Soviet of the Union - is composed of representatives from single-member districts, each containing about 360,000 persons. It is for this body that Saikin is running. When he is elected, he says , he would like to devote some of his energies to studying transport problems - a seemingly appropriate task for a man who heads more than a dozen factories that turn out trucks as well as passenger cars.

All of the candidates for the Soviet of the Union - including Saikin - are nominated by unions, work collectives, or the myriad other ''public organizations'' allowed under the country's Constitution to name candidates. Theoretically, a number of candidates are nominated in each constituency. Representatives of the nominating organizations then meet and choose a single candidate.

In fact, the entire process is carefully scrutinized by the Communist Party leadership. Thus, Soviet officials are proud to point out that a majority of the people serving in the current Supreme Soviet - 51.1 percent, to be exact - are ''factory workers and peasants.'' A third are women, a fifth are under the age of 30.

In the current Supreme Soviet, says a Soviet analyst, only about half of the candidates are Communist Party members.

On election day this Sunday, voters will make their way to thousands of polling places and cast their votes. The voting is done publicly, and consists of merely collecting a ballot (which has only one candidate's name on it) and dropping it, unmarked, into a box. A voter can choose to spoil it or write in another candidate, but must make a conspicuous walk to a separate area of the polling place. Less than 1 percent of Soviet voters chose to do so during the last election.

Although there is no law compelling citizens to vote, they will be cajoled (some might say coerced) by thousands of canvassers Saikin says he has more than 100 ''agitators'' working in his district alone.

It has not always been that way. In the 1930s and 1940s, the turnout was around 50 to 60 percent. That, says a Soviet official, was a result of ''people refusing to endorse the Communist Party platform.''

''Now,'' he says with a touch of pride in his voice, ''practically speaking, such people do not exist.''

Some Western analysts argue that elections here are not an empty exercise. They say that the mere act of casting a ballot involves the Soviet populace in the political process, albeit in a none-too-profound manner. Other Western observers are not so charitable, saying the exercise is just a cynical attempt to give a thin veneer of legitimacy to the Communist regime.

Soviet officials hotly disagree, arguing such criticisms merely point up a lack of understanding of the Soviet system.

''Our deputies don't go with their own program,'' says a Soviet analyst. ''They all have the same program. So the choice is made on the individual's ability.''

While the Soviet government does not welcome criticism of its electoral system, it apparently feels quite free to dispense criticism of Western-style democracy.

Tass, the official Soviet news agency, notes that while half the deputies in the Supreme Soviet are workers and peasants, businessmen and bankers account for 83 percent of the United States Congress. There are no workers at all in the US Senate, Tass points out, while fully half the senators are millionaires.

Tass adds that ''much less than half of the registered electors participate in elections to Congress.'' That is because ''representatives of . . . monopoly capital'' are the true ''masters of the country.''

Western-style democracy, says Tass, is a political system ''which is more and more discrediting itself.''

On the other hand, Tass notes that under the Soviet system there is ''invariably progressive development.''