Andrew Jackson was an unhappy man in the fall of 1825. Nominated for the presidency as the candidate of the South and West, he had tallied 99 electoral votes, more than any of his three competitors. But his failure to gain an outright majority threw the election into the House of Representatives, where Henry Clay--a distant fourth-place finisher in the initial balloting--donated his votes to John Quincy Adams, allowing the New Englander to sneak off with the keys to the White House.

Since Adams' back door victory, no election has been decided in the House, and as John Anderson's dreams crumble, it seems unlikely that a deadlock will arise this year. Undaunted, constitutional trivia buffs will doubtless spend much of Tuesday arguing about the dusty regulations governing a deadlock Electoral College and about such prospects as a Walter Mondale Acting Presidency.

If Congress gathers on January 6th to open the ballots officially and discovers that Anderson has grabbed Massachusetts, it may also find that neither Reagan nor Carter has garnered the 270 electoral votes needed to win the election. What then?

If no candidate has won a majority, the House chooses a winner from among the top three finalists in the Electoral College derby. Each state delegation has one vote; split delegations must abstain. Meanwhile, the Senate picks a vice president, with each senator casting a single vote.

The fun begins if the House gives no one the 26 votes needed for a win. If the wheeling and dealing continues without resolution beyond Inauguration Day, January 20, the vice president becomes acting president until the deadlock is broken. Although elected by a mere 100 people, he may reside indefinitely at 1600 Pennsylvania Avenue.

Because the new Congess elected Tuesday would preside over a possible deadlock, analysts say a Carter-Mondale victory would not be guaranteed. Democrats now control both houses, but their rivals expect to gain ground on November 4. Even if the Democrats retain their majorities--as they probably will--the GOP could gain enough key House seats to deny them the 26 Democratic delegations Carter would need for a clear victory. All eyes would then shift to the other side of the Capitol, where regardless of a likely Republican net gain the Democrats will remain in power, and Mondale would have little trouble outpolling George Bush. The Marine Corps Band could conceivably be playing "Hail to Fritz" until 1983, when a new Congress would try to pick a permanent president.

If Anderson did take Massachusetts or Connecticut (the only two states where he has much of a chance), the Illinois representative could use his electoral booty to buy favor with one camp and thus end the feuding early. Both Carter and Reagan would certainly woo the Illinois congressman, as they would the electors them-selves, who, after all, are not forced by the Constitution to vote for the candidate they promised to support. (Many states have passed laws to rein in rebellious electors, but they do occasionally slip away.) a dramatic historic event which would result in change," says Edward C. Banfield, Markham Professor of Government and an expert on American political reform. "Apprehensions about the electoral college system that have existed, but not in a significant way, will be acted on."

Legislators traditionally toy with direct-election schemes after tight presidential races, such as John F. Kennedy's '40 squeaker over Richard M. Nixon in 1960. But laziness and hard lobbying by the small states that benefit from the current system have always bogged down reform efforts. A House-determined president might change some minds.

Who would dominate the proceedings in a potential 1980 deadlock? "The press would emerge as the great interpreter of the public mind," Banfield believes. "Politicians would look to the press before acting in that situation. Whether or not the people gave [it] that role, the press would assume it."

Banfield believes Carter "would be able to manipulate the advantages of the incumbency" to prevail in a House tussle, even if the Republicans do gain ground this week. But even if the struggle is protracted, Banfield says he "can't imagine a catastrophe that would leave us without a functioning political mechanism. If you call what we are doing now 'functioning,' we would carry on."