By John Whitesides, Political Correspondent

WASHINGTON, Oct 7 (Reuters) After slowly wilting as a top U S campaign issue, corruption is back in the spotlight with a seamy sex scandal and a torrent of accusations about what Republican leaders knew and when they knew it.

Democratic attacks on a Republican ''culture of corruption'' and abuses of power mostly fell flat with voters in the early run-up to next month's congressional elections, partly because some Democrats were tainted with similar influence-peddling charges.

But the lurid Capitol Hill sex scandal involving Republican Rep. Mark Foley gives Democrats another chance to make their case amid growing Republican concerns about the scandal's impact on the November 7 battle for control of the U S Congress.

''Now Democrats can say you have sex in this case, greed in the other cases and incompetence in the prosecution of the Iraq war. Maybe that all starts to add up,'' said Linda Fowler, a political scientist at Dartmouth College in New Hampshire.

Foley became the fourth Republican House of Representatives member in the last year to resign under an ethics cloud after lewd Internet messages he sent to teenage male congressional assistants became public.

The unfolding controversy and charges of a cover-up by Republican House leaders are just the latest stain on a campaign already marked by scandals featuring Scottish golf trips, yachts, Rolls Royces and a freezer stuff with ,000 in cash.

But voters often shrug off corruption allegations unless their lawmaker is directly involved, analysts say, and even the whiff of scandal has not been a certain career killer.

Despite ethics troubles, a handful of prominent lawmakers led by Republican Sen. Conrad Burns of Montana and Democratic Rep. William Jefferson of Louisiana are still battling for their political lives in close re-election races.

Burns has been hobbled by links to Republican lobbyist Jack Abramoff, who plead guilty to defrauding clients and conspiring to bribe lawmakers. Burns, in a close race with Democrat Jon Tester, had to return donations from Abramoff associates.

COLD CASH Jefferson is battling a dozen challengers after being caught with ,000 in cash in his freezer by investigators looking into telecommunications deals in Africa and elsewhere.

Democratic Sen. Robert Menendez of New Jersey has been hit with questions about his financial dealings with a nonprofit group, while Democratic Rep. Alan Mollohan of West Virginia has faced accusations he funneled congressional spending earmarks into nonprofit organizations he created and controlled.

The race where the Foley scandal could have a big impact is in Pennsylvania, where Republican Rep. Don Sherwood is trying to overcome his own sex scandal and can hardly afford to remind voters of his indiscretions.

Sherwood, who is married, last year publicly acknowledged a five-year extramarital affair and settled a lawsuit with his former mistress.

Exhibits A and B in the Democratic case for Republican corruption this year have been former Reps. Tom DeLay of Texas and Bob Ney of Ohio, who both resigned from Congress under duress.

Ney agreed to plead guilty to corruption charges related to Abramoff, who provided him trips to places like the fabled St.

Andrews golf course in Scotland in exchange for favors on legislation.

DeLay, who had two top aides convicted in Abramoff-related cases, faces state campaign finance charges in Texas.

Late last year, Republican Rep. Randy Cunningham of California resigned and was later sent to jail for accepting WASHINGTON, Oct 7 (Reuters) After slowly wilting as a top U S campaign issue, corruption is back in the spotlight with a seamy sex scandal and a torrent of accusations about what Republican leaders knew and when they knew it.

Democratic attacks on a Republican ''culture of corruption'' and abuses of power mostly fell flat with voters in the early run-up to next month's congressional elections, partly because some Democrats were tainted with similar influence-peddling charges.

But the lurid Capitol Hill sex scandal involving Republican Rep. Mark Foley gives Democrats another chance to make their case amid growing Republican concerns about the scandal's impact on the November 7 battle for control of the U S Congress.

''Now Democrats can say you have sex in this case, greed in the other cases and incompetence in the prosecution of the Iraq war. Maybe that all starts to add up,'' said Linda Fowler, a political scientist at Dartmouth College in New Hampshire.

Foley became the fourth Republican House of Representatives member in the last year to resign under an ethics cloud after lewd Internet messages he sent to teenage male congressional assistants became public.

The unfolding controversy and charges of a cover-up by Republican House leaders are just the latest stain on a campaign already marked by scandals featuring Scottish golf trips, yachts, Rolls Royces and a freezer stuff with $90,000 in cash.

But voters often shrug off corruption allegations unless their lawmaker is directly involved, analysts say, and even the whiff of scandal has not been a certain career killer.

Despite ethics troubles, a handful of prominent lawmakers led by Republican Sen. Conrad Burns of Montana and Democratic Rep. William Jefferson of Louisiana are still battling for their political lives in close re-election races.

Burns has been hobbled by links to Republican lobbyist Jack Abramoff, who plead guilty to defrauding clients and conspiring to bribe lawmakers. Burns, in a close race with Democrat Jon Tester, had to return donations from Abramoff associates.

COLD CASH Jefferson is battling a dozen challengers after being caught with $90,000 in cash in his freezer by investigators looking into telecommunications deals in Africa and elsewhere.

Democratic Sen. Robert Menendez of New Jersey has been hit with questions about his financial dealings with a nonprofit group, while Democratic Rep. Alan Mollohan of West Virginia has faced accusations he funneled congressional spending earmarks into nonprofit organizations he created and controlled.

The race where the Foley scandal could have a big impact is in Pennsylvania, where Republican Rep. Don Sherwood is trying to overcome his own sex scandal and can hardly afford to remind voters of his indiscretions.

Sherwood, who is married, last year publicly acknowledged a five-year extramarital affair and settled a lawsuit with his former mistress.

Exhibits A and B in the Democratic case for Republican corruption this year have been former Reps. Tom DeLay of Texas and Bob Ney of Ohio, who both resigned from Congress under duress.

Ney agreed to plead guilty to corruption charges related to Abramoff, who provided him trips to places like the fabled St.

Andrews golf course in Scotland in exchange for favors on legislation.

DeLay, who had two top aides convicted in Abramoff-related cases, faces state campaign finance charges in Texas.

Late last year, Republican Rep. Randy Cunningham of California resigned and was later sent to jail for accepting $2.4 million in bribes, including a yacht and a Rolls Royce, from defense contractors.

But just months later a Republican lobbyist, former congressman Brian Bilbray, won a special election in California to replace Cunningham, highlighting the corruption issue's limited impact on voters.

''By the time the election was held, Cunningham was in jail and voters had moved on,'' said Jennifer Duffy, a Senate analyst for the nonpartisan Cook Political Report.

REUTERS PDM HT0904 .4 million in bribes, including a yacht and a Rolls Royce, from defense contractors.

But just months later a Republican lobbyist, former congressman Brian Bilbray, won a special election in California to replace Cunningham, highlighting the corruption issue's limited impact on voters.

''By the time the election was held, Cunningham was in jail and voters had moved on,'' said Jennifer Duffy, a Senate analyst for the nonpartisan Cook Political Report.

REUTERS PDM HT0904