WASHINGTON (Reuters) - Congressional Democrats stepped up attacks on what they called Republicans' "culture of cronyism and corruption" on Thursday, trying to capitalize on a spate of ethics scandals and the Bush administration's heavily criticized response to Hurricane Katrina.

Although congressional elections are still more than a year away, Democratic leaders -- often accused of not being able to articulate a clear party message -- held a series of news events in which they sought to link allegations of corruption and government incompetence.

The fiasco over the response to Hurricane Katrina "sort of pulled up the curtain and exposed the whole mess," said Sen. Charles Schumer (news, bio, voting record) of New York, who heads up the Democratic election effort for the Senate.

"We as a party are going to be the broom that sweeps things clean."

While declining to make any specific predictions of gains in the November 2006 elections, Illinois Rep. Raum Emanuel, who heads the House Democrats' campaign committee, said the vote would become a national referendum on "change and reform."

Senate Minority Leader Harry Reid outlined Democrats' plans to draft legislation to tighten lobbying rules and require people appointed to public safety positions to have relevant credentials and a "superior" track record.

"We're going to reform Washington," Reid said. "After years of Republican scandals and abuses of power, it's a big task. But the American people are demanding change."

Two influential House Democrats, Rep. John Conyers of Michigan and Rep. George Miller sof California, called for a special counsel to probe the scandal surrounding Washington lobbyist Jack Abramoff's possible ties to Justice Department officials.

And House Democratic leader Nancy Pelosi of California and her deputy Rep. Steny Hoyer of Maryland renewed calls for the House ethics committee to investigate Rep. Tom DeLay, the Texas Republican forced to step down as House majority leader after he was indicted on charges related to campaign financing.

Republicans have also been buffeted by an SEC investigation of Senate Majority Leader Bill Frist of Tennessee over a stock sale, the multifaceted probe into Abramoff's activities, and the related arrest this week of former White House aide David Safavian.

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