What will we know when we know it?

When we learn, less than a week from now, who has won and who has lost in the elections of 1982, what will we be able to say about the direction the country is going?

That question is always harder to answer in a mid-term election than in a presidential year. And this year it is tougher than normal -- in part because of the kind of election we had in 1980.

That was as close to a mandate as we are ever likely to see in this country, with our loose-knit, non-ideological parties. Ronald Reagan, an issue-oriented man all of his political life, laid out a fundamental critique of the policies of the Democratic administration and Congress, and he suggested very clearly the direction of the changes he would make.

Those changes -- a shift of resources from domestic programs to national defense, a sharp reduction in taxes and a slowdown in domestic spending, a cutback in federal regulatory activity and a transfer of responsibilities to the states -- were embraced by his party and the vast majority of its candidates. And they became the basis of the legislative program that was passed when Republicans gained actual control of the Senate and working control (with conservative southern Democrats) of the House.

Had that program produced the kind of vigorous economy that Reagan and other advocates predicted when lobbying for its passage in 1981, this mid-term election would have been an endorsement of -- not a referendum on -- Reaganomics. Quite plausibly, given the GOP's advantages in money and organization, it would have been the opportunity for the Republicans to establish themselves as the long-term party of government.

It is plainly not going to be that. Because the election occurs at a time of historically high unemployment, low farm income and serious threat of bankruptcy to both large manufacturers and small retailers, Republicans cannot hope for a positive endorsement of their program.

All they can do is point to the progress on inflation and interest rates and hope to persuade people that they are auguries of better times to come. "Stay the course," may not be the most invigorating battle cry in history, but there was no other the Republicans could plausibly make.

But as my colleague Mark Shields pointed out the other day, Republicans are playing this election "not to lose, and that is different from playing to win."

By nationalizing the debate, with their "stay the course" advertising drive and the visible participation of the president and vice president in dozens of campaigns, Republicans have raised the stakes in this election. The Washington Post-ABC News polls of closely contested House districts show that confidence or lack of confidence in Reaganomics is the best predictor of how people will vote.

So there will be an element of referendum in the election results. But as always, in a mid-term, it will be clouded by factors special to the particular state or district. Many of the likely Republican survivors are men and women who have managed to put some distance between themselves and the Reagan program.

But beyond that, the referendum element is limited by the fact that voters themselves recognize this is simply an interim judgment. The Democrats cannot take control of national policy this year. They cannot elect a president or establish veto-proof majorities in both the House and Senate. The short-term operative question is whether Reagan can retain enough support to further the plans he laid out in 1980 or whether Democrats gain the strength to stay his hand at least through 1984.

Two facts are critical from Reagan's point of view. Republicans must retain their Senate majority to ensure the president's proposals get a priority place on the legislative agenda. That is the most vital of all objectives, for without the Senate his plans might never even earn a hearing. If they pick up five seats and take over the Senate, Democrats could use the committees of Congress to harass the administration and focus on the issues they prefer for the 1984 campaign.

The second priority is keeping the Republican-southern Democratic coalition in control of the House. If Republicans lose only the dozen seats that have been average for the first mid-term election after change of party control of the White House, they will still be in the driver's seat. If they lose the 30 to 40 seats some polls are predicting, conservative coalition control is shattered. In between, in the 20- to-25-seat range, it will require skill and concessions on Reagan's part, but give him leverage on most if not all issues.

Measured in those terms, it ought to be a right-interesting election.