The US: Tom DeLay, former Republican leader of the House of Representatives, who has been indicted on conspiracy and money-laundering charges, is attempting to subpoena a Texas prosecutor to compel him to answer questions about his conduct of the case.
Mr DeLay claims that Travis County District Attorney Ronnie Earle, a Democrat, tried to coerce two grand juries into indicting him.
Meanwhile, the Republican leader in the Senate, Bill Frist, faces new questions about suspicious share dealings which are under investigation by the Securities and Exchange Commission, the body that polices stock exchange transactions.
Mr DeLay stepped aside as House leader after he was indicted on September 28th for conspiring to violate a Texas ban on corporate contributions to political campaigns in 2002. He claims that, when Mr Earle realised that the indictment could be thrown out because the alleged crime did not reach the statute books until 2003, he scrambled to file new charges against him.
A second grand jury refused to indict Mr DeLay, but a few days later a new grand jury indicted him on charges of money-laundering and conspiracy to launder money related to the corporate contributions.
Mr DeLay's lawyers say that Mr Earle unlawfully talked to members of the first grand jury after they were discharged and reported those conversations to the new grand jury to persuade them to issue the money-laundering charges.
A brief filed this week by Mr DeLay's lawyers states: "During the five-day period of September 29th, 2005 to October 3rd, 2005 Ronnie Earle and his staff engaged in an extraordinarily irregular attempt to contrive a viable charge and get a substitute indictment of Tom DeLay before the expiration of the statute of limitations on October 3rd, 2005."
Grand jury secrecy laws mean that Mr Earle is unlikely to be asked to testify, but the subpoena underscores the Republican congressman's determination to fight the charges against him. Despite stepping aside as House leader, Mr DeLay, who is known as "The Hammer", remains a powerful figure on Capitol Hill and has made clear that he expects to return to his leadership role.
Mr Frist's attempts to escape censure over his share dealings suffered a setback yesterday when the Associated Press news agency reported that new documents showed he earned tens of thousands of dollars from shares in a hospital chain run by his brother.
Mr Frist has consistently claimed that he could vote on healthcare legislation because all his investments were held in blind trusts.
The Securities and Exchange Commission began investigating Mr Frist's investments after he asked administrators of his blind trusts to sell his shares in HCA, his brother's hospital chain, on June 13th.
All sales were completed by July 1st. HCA's share price peaked on June 22nd and then gradually declined. On July 13th, it fell by 9 per cent.