House Democrats get tough on the exterminator: Top House Democrats today condemned Representative Tom DeLay, the leader of the Republican majority, declaring that the latest ethics case against him proved that he had been corrupted by power and was unfit to lead. "The ethical cloud that has been hanging over the Capitol has burst," Representative Nancy Pelosi of California, the Democratic leader, said at a news briefing. "Mr. DeLay has proven himself to be ethically unfit to lead the party.` Other prominent Democrats joined Ms. Pelosi in condemning Mr. DeLay and calling for his replacement during a question-and-answer session that seemed to signal a new level of partisan bitterness in the House with elections less than four weeks away. "Isolated incidents may be rationalized and minimized, but consistent patterns are powerful proof of corrupt practices," said Representative Steny H. Hoyer of Maryland, the Democratic whip.