Washington ? The number of competitive Senate races has edged up in recent months, buoying Democratic hopes of minimizing their losses and possibly even winning a majority in the November elections.

Republicans scoff at the notion of a Democratic takeover, and many independent observers say odds still favor continued GOP control of the Senate, probably with at least some gains in the party’s current 51-vote majority in the 100-member chamber.

But there is a growing view among political analysts that Democratic gains can no longer be ruled out — a view reinforced by the decision of Sen. Ben Nighthorse Campbell, R-Colo., to retire.

“The situation for Democrats looks a whole lot better than it did six weeks ago … but Democrats need a lot to go right for them to reach 51,” said Jennifer Duffy, who oversees Senate races for the Cook Political Report.

Democrats need a net gain of only one or two seats to win control of the Senate: one seat if voters elect a Democrat as vice president, who breaks ties in the Senate; and two seats if they elect a Republican.

For Democrats, the big break came March 3 when Campbell, who had been favored to win re-election, announced he would not seek another term. Although Colorado leans Republican, Campbell’s decision put the state in play.

Other key states

l An earlier break for Democrats came late last year when Sen. Don Nickles, R-Okla., announced he would not run again this fall, providing an opening that Democrats were quick to exploit. Rep. Brad Carson, a Democrat who jumped quickly into the race, is heavily favored to win his party’s nomination and has run ahead of Republicans in a recent poll.

l Probably the best targets for Democratic gains are Democratic-leaning Illinois, where first-term Republican Sen. Peter Fitzgerald decided against seeking re-election, and Alaska, where Republican Sen. Lisa Murkowski was appointed to the seat by her father when he left the Senate to become governor. Illinois will choose its nominees in a primary Tuesday. In Alaska, Lisa Murkowski is opposed by former Gov. Tony Knowles.

With the recent signs of progress for Democrats in Senate races, Democratic Senatorial Campaign Committee Chairman Jon S. Corzine, N.J., called a news conference earlier this month to declare that the Senate is “now officially up for grabs.”

But Democrats do start out with disadvantages, including the retirement of Democratic senators in five states: John Edwards, North Carolina; Ernest Hollings, South Carolina; Zell Miller, Georgia; Bob Graham, Florida, and John Breaux, Louisiana.