How small parties could hold the reins in West Germany

A reelected conservative Chancellor Helmut Kohl - but a watchdog team of environmentalist-nuclear pacifist Greens in the Bundestag. This is the eve-of-election outlook as West Germans go to the polls March 6.

The conservatives - Mr. Kohl's Christian Democratic Union in northern and western West Germany, and Franz Josef Strauss's Christian Social Union in Bavaria - are expected to take either a majority or just under a majority.

The conservatives' junior coalition partner, the Free Democratic Party (the Liberals), is expected to survive by winning the 5 percent minimum for seats in the Bundestag (parliament), and to maintain its traditional position as the balance wheel of Bonn politics.

The protest movement of the Green Party is also expected to cross the 5 percent threshold for the first time, completing its transition from outside critic to inside political participant.

The main opposition party, the Social Democrats led by Hans-Jochen Vogel, is expected to win a percentage in the low 40s or high 30s - not enough to form a government, even if it were ''tolerated'' by the Greens.

West German pundits tend to regard unemployment and recession, not NATO missles, as the most decisive issues for voters. Seasonally-unadjusted figures released March 3 showed a new high of over 2.5 million, or 10.4 percent of the work force, unemployed. Here there is relatively little difference in the specific programs of right and left: Both are for pulling the economy out of il 23l,0,12l,7p6recession and creating more jobs. Kohl has been campaigning hard, however, as the person who could restore business confidence, investment, and thus growth. For their part, the Social Democrats have said while they too would trim social welfare, they would trim it more fairly than the conservatives.

The most virtuoso acts in the campaign have been those of the smallest parties.

The Greens, with no money to speak of and with no comprehensive organization at the beginning of the campaign, have captured in the past two years in six of the 11 state legislatures in West Germany.

And the Free Democrats have for two decades decided which of the two major parties would govern, acting as a brake on that governing party - holding back the Social Democrats' left wing and the conservatives' right wing, respectively.

After they toppled the popular Social Democratic chancellor, Helmut Schmidt, last fall, it looked as if the Liberals might have jumped coalitions once too often. Public opinion polls gave them a bare 3 percent nationwide.

Alarm over removing the Liberal check on the conservatives (and especially at having the Christian Social Union's volatile Strauss as vice-chancellor in Bonn) has now turned the tide back toward the Free Democrats. But Interior Minister Friedrich Zimmermann suggested to the Munich Press Club Thursday that Strauss could replace Foreign Minister Hans-Dietrich Genscher if Genscher's FDP gained less than 7 percent of the vote.

Also aiding the FDP is concern that a Liberal failure to clear 5 percent would then leave the unorthodox Greens as the political balance in the Bundestag.