THE BALLOT CAN BE an amazingly blunt tool for conveying political preferences. Ronald Reagan took his party's 1980 landslide as a national endorsement of a very specific right-wing agenda, and over the next two years he and his congressional colleagues proceeded to enact a shocking amount of the 1980 Republican platform. The beating taken by conservative candidates in last week's midterm elections suggests Reagan's interpretation was too hasty and too sweeping. America two years ago now appears to have been demanding an end to four years of Democratic ineptitude, not signifying broad support for supply-side economics, massive defense build-ups and the industrial gutting of the environment.

Last week's aggregate returns can be understood only as a reaction to the last two years of Republican rule. In the House of Representatives, the GOP lost some 26 seats, more than twice the midterm average; in almost no case did a conservative challenger unseat a liberal incumbent. In the Senate, despite the fact that the vast majority of seats up for grabs were held by Democrats, the Republicans only barely clung to their slim majority. At the state level, Democratic candidates took seven of the 14 contested governor ships previously held by Republicans. They also won control of the legislatures of some 35 states.

As in 1980, the electorate's message on specific issues remains harder to interpret, especially since Americans were voting on discrete state and local races and not one national contest. But on at least two issues--the economy and nuclear policy--some degree of consensus shone through

Economic concerns dominated the campaigns at all levels, and by all accounts they were foremost in voters' minds, too Exit poll after exit poll showed Americans to have voted their pocketbooks, with mounting unemployment and still-high interest rates being particular worries.

Both parties had framed the election as a referendum on whether the President should "stay the course" and pursue his economic policies of massive tax cuts, sharp reductions in social spending and huge increases in military expenditures. The clear answer America gave was "no"--and had the nation had the chance to express itself again later in the week, its answer might well have been even more resoundingly negative. New unemployment figures released Friday showed the national jobless rate had hit 10.4 percent, a new post-war high.

The nuclear arms race never became a major issue in most campaigns, but many Americans had the chance to register their feelings in statewide referenda. Ballots in nine states included nonbinding questions asking voters either whether they supported a moratorium on the production of nuclear weaponry, or whether they backed a mutually verifiable nuclear freeze. In eight of the nine states, voters said "yes"--including the Bay State, which logged in with nearly 70 percent of voters in favor of a moratorium. The nine simultaneous referenda together constitute the closest thing to a national referendum in American history, and as such deserve recognition as a very credible barometer of national sentiment on the nuclear issue.

The President can disregard these clear sentiments and gamble that his still-immense personal popularity can tide himself and his party through the 1984 election. But that would be a high-risk move, indeed, and it would do nothing to alleviate the nation's growing fears on both the nuclear and economic fronts.

He would do better to consider seriously Democratic proposals for a nuclear arms freeze and for a massive public works program for the jobless--and, in general, to seek bipartisan compromise. For if Reagan ignores last week's show of dissatisfaction with his policies by clinging to his 1980 agenda, he will succeed only in proving that his moniker as "The Great Communicator" refers only to his ability to talk, not to listen.