The Republican drive to narrow the Democrats' margin of control in the Senate has been blunted by the continuing preoccupation with the Persian Gulf crisis, raising hopes among Democrats that they can weather the Nov. 6 elections without major losses.

Despite promising starts by several Republican challengers and a strong anti-incumbent mood among voters, all but one of the 17 Democratic senators who are seeking reelection are running ahead of their GOP opponents as they enter the final six weeks of the campaign.

But support for many of the Democrats is wider than it is deep, and some Republican challengers are only now beginning heavy campaigning. Even the Democrats concede there is what they describe as a "potential for volatility" that could erase many of their leads in a matter of days.

"When you combine the cynicism that people have about the whole process with events in the Persian Gulf that have diverted attention from the campaigns, you're going to have some late-breaking races," said Larry Harrington, political director for the Democratic Senatorial Campaign Committee.

Until Iraq invaded Kuwait in early August, "the throw-the-bums-out issue was coming on strong," said Sen. Don Nickles (Okla.), chairman of the National Republican Senatorial Committee. "The gulf crisis may have displaced it temporarily, but it's still there."

Sen. John Breaux (La.), chairman of the Democratic campaign committee, put it another way. "People are saying it's bad but it's not my guy's fault," he said.

However, nearly all agree that this election, more than most, will test the long-standing love-hate relationship that voters have with Congress: hate Congress, love their own member.

Among Democrats, only the recently appointed Sen. Daniel K. Akaka of Hawaii is running even or trailing. Republicans say that recent polls show Rep. Patricia F. Saiki (R) leading Akaka; Democrats say the race is a draw.

But the tight race in Hawaii is offset by a similarly close contest in North Carolina, where Sen. Jesse Helms (R) is running even with former Charlotte mayor Harvey Gantt (D), according to strategists for both parties.

While a trade of Hawaii for North Carolina would leave the Democrats with the same 55-to-45 advantage they now enjoy, there are at least a half-dozen other races regarded as competitive even though some of the incumbents currently lead by substantial margins. All of them, except Kentucky, involve GOP challenges to vulnerable Democratic incumbents, including:

Rhode Island, where a recent poll showed Foreign Relations Committee Chairman Claiborne Pell (D) widening his lead over Rep. Claudine Schneider (R) to double digits in a race pitting experience against youthful vigor.

Iowa, where Sen. Tom Harkin (D) clings to an 8- to 10-point lead over Rep. Thomas J. Tauke (R) although Republicans say Tauke is starting to climb.

Illinois, where independent polls show Rep. Lynn Martin (R) trailing Sen. Paul Simon (D) by as many as 25 points, although Simon's involvement in a savings and loan controversy could cause him problems.

Nebraska, where Sen. J. James Exon (D) leads former representative Hal Daub (R) by at least 12 points, with Republicans hoping Daub's aggressive style and the state's strong Republican traditions will soon narrow the margin.

Michigan, where polls show Sen. Carl Levin (D) with a big lead over Rep. Bill Schuette (R) that even Democrats expect to narrow.

Kentucky, where Democratic voting habits make Sen. Mitch McConnell (R) an inviting target for Jefferson County (Louisville) executive Harvey Sloane (D), although Republicans say McConnell's lead has widened to 15 points.

There are a handful of other races being closely watched by both sides, including long-shot challenges to Sen. Larry Pressler (R-S.D.) and Max Baucus (D-Mont.). Republicans are now tantalized by Massachusetts, where they believe Sen. John F. Kerry (D) could get whipsawed by the voter fury that contributed to upsets in last Tuesday's primaries. However, most of these second-tier, potentially competitive races involve seats now held by Republicans, including those being vacated by retiring Sens. William L. Armstrong (Colo.), Gordon J. Humphrey (N.H.) and James A. McClure (Idaho).

For the rest of the 35 seats at stake this year, incumbents will win in a walk. Of the 32 incumbents seeking reelection, 16 have little or no opposition, reflecting the waning competitiveness of Senate as well as House races.

More important than current rankings is the fact that big surges often come in a campaign's final week or so -- a phenomenon that could be even more pronounced this year as candidates scramble to make up for lost time.

There is also the reluctance of voters to rock the boat during a storm, which could help explain why incumbents fared so well during early weeks of the gulf crisis. If the crisis continues, incumbents may continue to benefit. But if tension subsides, so may the incumbents' leads, some believe.

"I'm optimistic. I think we will pick up some seats," said Nickles. "If we won all the close ones, we could take control, but that's not probable."

"I'd be satisfied if we hold our own," said Breaux, who said he believes Democrats are now holding steady or gaining.

With a 10-vote margin going into the election, the Democrats can afford to lose a few seats and retain control of the Senate for the next two years. Their problem is that this year's fight is just the opening skirmish of the real war for control in 1992, when Democrats will be defending the bumper crop of seats they won, many by small margins, in recapturing the Senate in 1986. Democrats need a good cushion going into 1992, to say nothing of 1994, when they again will be defending far more seats than the Republicans. So every seat counts this year.

While Democrats probably have the most to lose from a "throw-the-bums-out" mood, the message gets blurred in most of the key races because the Republican challengers are longtime members of the House, according to Democratic strategists.

"It's a case of our 'bum' versus your 'bum,' " said one Democrat.

Concern over the economy helps the Democrats most, but anger over the savings and loan fiasco and other ethics-related issues is expected to cut both ways. Except for fund-raising, even Republicans say President Bush's popularity will not be of much help to GOP candidates.

The current budget stalemate is a cause for anxiety, especially among incumbents. Failure of budget negotiations, which would trigger massive spending cuts just before the elections, could crystallize the impression of rampant ineptitude in Washington and move voters to clean house.

Republicans seized an early edge by recruiting more experienced candidates, mostly House members, reversing the advantage that Democrats enjoyed over the past several election cycles. But in states such as Illinois and Iowa, some have had trouble achieving statewide recognition, while the Democratic incumbents have proven to be more aggressive and resilient than many expected.