WASHINGTON - The sexual harassment allegations engulfing the candidacy of Republican Herman Cain dominated American politics Tuesday as prominent conservative voices rallied to his side, saying he was the victim of the same kind of "high-tech lynching" that roiled the nomination of Supreme Court Justice Clarence Thomas.

Cain has been pointing to his long record in business to argue that he has the credentials to be president during a time of economic hardship -- a small government, anti-tax message that has struck a deep cord with conservatives.

Supporters were quick to liken Cain's troubles to those of Thomas, another prominent black conservative, who also faced sexual harassment allegations during his explosive Senate confirmation hearing two decades ago.

The forceful early reaction to the Cain firestorm -- fueled by racially charged rhetoric -- suggests the Georgia businessman's attempt to cast himself as a victim of the news media and liberals is, so far, paying dividends among his conservative Republican base who will hold considerable sway in selecting the party's nominee.

But the accusations against Cain may give more moderate Republican voters pause and could cause would-be donors to shy away even as Cain works to capitalize on his rising poll numbers.

It's not the first time Cain has had to explain himself since his quick climb in the polls. The political newcomer had a series of fumbles and has had to clarify comments on abortion, immigration and terrorism suspects.

Cain is again on the defensive after a report on the Politico website that said the National Restaurant Association gave financial settlements to at least two female employees who had accused him of inappropriate sexual behaviour when he was its chairman.

The Milwaukee Journal Sentinel newspaper, meanwhile, reported that Cain allowed a tax-exempt charity to illegally provide money to help his presidential campaign get started. Cain's chief of staff, Mark Block, says the campaign has asked a lawyer to review the transactions.

On Monday, the candidate declared he had been falsely accused of sexual harassment in the 1990s while he was head of the restaurant trade group. He said the allegations that are surfacing now are part of a "witch hunt." He has, however, given varying responses to questions about whether there were financial settlements with the women who brought the complaints.

The Politico report was based on anonymous sources and, in one case, what the publication said was a review of documentation that described the allegations and the resolution. Politico said Cain refused to comment when asked specifically about one of the woman's claims.

Cain was skipping a gathering Tuesday of fellow party hopefuls in Iowa where they were to outline their plans for fixing the damaged U.S. economy. On Jan. 3, Iowa will be the first American state to formally select a favourite Republican candidate for nomination to challenge President Barack Obama in the November 2012 election.

Cain has been taking an unorthodox path in his campaign, largely eschewing early voting states to focus heavily on the South -- where tea party groups, social conservatives and evangelical voters that make up the backbone of his support hold sway.

Also absent from the Iowa forum will be Cain's fellow front-runner, former Massachusetts Gov. Mitt Romney, who has sought to stay above the inter-party scramble that has seen other would-be Obama challengers shoot to the top of the Republican nominating heap only to plunge dramatically and quickly out of contention.

Attending the session sponsored by the state's Republican Gov. Terry Branstead will be Texas Gov. Rick Perry, who looks to the Iowa contest to steady his campaign after stumbling in recent weeks. He planned to tout his role in keeping jobs growing in his state during the recession.

Also signed up is Ron Paul of Texas. Recent polling in Iowa shows Paul running third to Cain and Romney, who are virtually tied.

Cain spent Monday in Washington, answering questions about why the restaurant trade group he once led paid to settle sexual harassment complaints against him. He planned another day in Washington on Tuesday, trying to quiet concerns that could drag down his meteoric rise in polling.

Aides to Romney, the successful venture capitalist who pitches himself as the best opponent to Obama on the economy, said he had a scheduling conflict that prevented him from joining. Romney planned to return to the campaign trail Thursday in New Hampshire. That state will hold the first primary vote in the nation shortly after the Iowa caucuses;

Without that pair, the event seemed more an opportunity for the Republicans' second tier to make a pitch while honing attacks on Obama -- and probably on each other. The rivals are not set to face each other directly, yet the new sense of urgency in the campaign is likely be on display as each seeks to distinguish himself or herself just two months before Iowa's caucuses.

Cain, who is best known for his management of a pizza restaurant chain, stunned the political establishment with his rise from national obscurity to place at or near the top of national surveys and polls in early presidential nominating states. He is, competitive with Romney, long considered the front-runner for the nomination.

The Politico report was based on anonymous sources and, in one case, what the publication said was a review of documentation that described the allegations and the resolution. Politico said Cain refused to comment when asked specifically about one of the woman's claims.