Opening statements have begun in the money laundering trial of former US House Majority Leader Tom DeLay, who prosecutors say channelled money into Texas legislative races in 2002.
Mr DeLay, is accused of illegally funnelling corporate money into races to build his political influence.
The 63-year-old Republican, who was nicknamed "the Hammer" for his forceful style in Congress, denies wrongdoing.
Mr DeLay's attorneys say he is guilty only of being a good politician.
Prosecutor Beverly Matthews said the former lawmaker had collected $190,000 (£118,000) through a group he had started and had piped the money into the Washington-based Republican National Committee to help Republican state legislative candidates.
The national committee then used money gathered from individual donations to send $190,000 to seven Republican candidates in Texas, she said.
It is illegal in Texas for corporate money to be directly used for political campaigns.
"The evidence will show you they took the corporate money they knew could not be given and came up with a scheme where that dirty money could be turned clean and given to candidates," Ms Mathews said.
Mr DeLay, who is charged with money laundering and conspiracy to commit money laundering, has denied acting illegally.
He was forced to resign his leadership post because of the indictment and later stepped down as a congressman.
If convicted, he could face up to life in prison.