Washington — In the 1984 congressional elections, the race often went not to the swift, but to the well-funded. There were 12 close Senate races this year, in which the winners got 60 percent or less of the vote. Eight were won by the candidates who spent more money, according to an analysis of postelection finance reports.
In House of Representatives contests, the advantage accruing to wealth was even greater. The richer candidates won in 40 of the 51 House races in which the victory margin was 55 percent or less.
Analyses of '84 campaign spending also disclosed that:
* House campaign spending leveled off in 1984, but Senate races kept on getting more expensive at a fast clip.
* Truly needy Democrats were well funded in '84 - a factor that may have snipped Reagan's coattails.
* The Republican Party, not usually at a loss for funds, may have let two Senate seats slip through its grasp. GOP Senate candidates Nancy Hoch in Nebraska and Chuck Cozzens in Montana almost won while being vastly outspent.
Of course, there are many factors in an election besides money. Incumbency, national political climate, and sheer personality all play large roles.
''The candidate who spends the most doesn't necessarily win,'' says Prof. Herbert Alexander of the University of Southern California, a noted campaign finance expert. ''But in a close race, any single expenditure might make a difference.''
The point in campaign finance is not so much to win a dollar race with your opponent as simply to spend enough. The most important thing cash buys for a candidate, say political scientists, is a chance to present his case. Oftentimes , huge sums just allow candidates to keep repeating their old case - which doesn't always help. This is particularly true for incumbents, who already have wide public exposure.
''If you're an incumbent, more money sometimes allows you to keep reminding voters why they're dissatisfied'' with you, says Michael Malbin, a resident fellow at the American Enterprise Institute.
The clearest example of this principle in 1984 was the West Virginia Senate race, in which Gov. Jay Rockefeller IV (D) outspent his opponent $11 million to
In politics, marginal dollars - those last few checks that trickle in near the end of the campaign - mean much more to challengers than they do to incumbents, Dr. Malbin notes. ''It's the single strongest correlation in campaign finance,'' he says. ''Spending by challengers (of marginal dollars) always means more votes.''
It is much harder, however, for challengers to raise these funds. Incumbents, almost always favored for reelection, usually do better at attracting money. A Monitor analysis of postelection finance returns, for instance, finds that the average senator in a competitive race spent $3.9 million dollars, while his challenger spent an average of $2.3 million.
Even the three sitting senators who lost - Charles Percy (R) of Illinois, Roger Jepsen (R) of Iowa, and Walter Huddleston (D) of Kentucky - outspent their opponents, although not by very much.
Races for open seats, for which there is no incumbent, tend to be the most expensive of all. The average candidate in this year's close open races for the Senate spent $4.8 million.
Overall, Senate candidates raised $125 million through Oct. 17, according to an analysis by Malbin. That's a 33 percent increase over 1982 levels.
House spending didn't rise nearly that fast, Malbin says. He found House campaign receipts to be $160 million through Oct. 17, a 10 percent rise over 1982.
The average House incumbent locked in a close race spent $469,700, while his or her challenger responded with $380,000, according to post-election figures.
Perhaps the most significant trend visible in this year's campaign finance figures is the rise in Democratic for-tunes. In 1982, much of the available Democratic cash was siphoned off by nervous incumbents.
This year, party leaders - in particular Rep. Tony Coelho (D) of California, chairman of the Democratic Congressional Campaign Committee - tried to make sure that serious House challengers and the open-seat candidates got enough cash.
In the 10 closely contested, open House races, Democrats on average actually outspent Republicans - $370,255 to $351,235 - according to postelection figures.