Washington — While polls and predictions only a few months ago pointed to Democrats retaking the United States Senate next year, the first skirmish has ended with a total victory for the GOP.
Virtually everything went right for the Republicans as the voters of Washington State elected Daniel J. Evans to serve the remaining five years of the term of the late Sen. Henry M. Jackson, a Democrat.
The Republicans had a tried and moderate candidate. A popular former governor , Mr. Evans planted himself firmly in the middle, not far from the much-loved senator whom he replaces.
''I think that 'Scoop' Jackson represented the mainstream of politics in our state,'' Evans recently told a breakfast meeting of reporters here.
His opponent, Rep. Mike Lowry, stood unabashedly on the most liberal wing of the Democratic Party.
World events dumped a windfall of issues on the GOP. For two weeks before the election Nov. 8, the country has been galvanized by a bombing of American soldiers in Lebanon and an invasion of Grenada.
The outspoken Mr. Lowry came down heavily against the Reagan administration in both crises, but voters apparently were moving the opposite direction. A Republican poll showed the state backing the President on Lebanon by two to one, and even greater support for the Grenada incursion.
Perhaps more important, the stirring international events stole away issues that might have boosted the Democrat.
''The polling showed jobs and education were good for Lowry,'' says Audrey Sheppard, campaign services director for the Democratic Senatorial Campaign Committee. But such subjects were out of place while the news was dominated by American soldiers fighting in the Caribbean or being bombed by terrorists.
Mitchell E. Daniels Jr., director of the National Republican Senatorial Committee, holds that Evans, not foreign events, won the election and that his polls showed the former governor ahead before the Grenada invasion. ''Grenada probably solidified the vote that was already there,'' he says.
Ties to the Reagan administration did not hurt the GOP candidate and may even have helped him.
Lowry set the tone of the campaign by accusing -Evans, appointed to replace Senator Jackson pending the election, of unvarying support of the President. Evans has denied that characterization, but he conceded that he has voted with the President so far because issues that divide them have not yet arisen.
Although the Lowry charge put Evans on the defensive and appeared to give the Democrat an early surge, by election day it became clear that supporting President Reagan would not defeat Evans, whose margin was a healthy 56.8 percent with 98 percent of vote tallied. The win is bigger than his 54 percent victory in the governor race of 1972.
The GOP formula of big money and a tight national organization worked once again. During the eight-week campaign, the Republicans amassed and spent up to $ 2 million. Moreover, the GOP had enough money to conduct polls every other night as the campaign heated up, while the Democrats conducted only a few polls and thus could trace the voter moods far less accurately.
There was no shortage of money on either side, however, since Lowry spent about $800,000, with the aid of his party.
Regardless of why it won, the Republican Party has plucked a plum in the apple-growing state of Washington. ''It's a major plus,'' says Mr. Daniels.
Shortly before his election, Evans played down the theory that the race would be a harbinger for 1984. ''Washington is a very independent state.''
But his win gives the GOP a firmer 55-to-45 grip on Senate seats, making it one seat harder for the Democrats to recapture the upper house. For President Reagan, it is one more green flag for his reelection possibilities, and evidence that at least his coattail did not hurt a GOP senator.