Former Illinois Governor Rod Blagojevich has appeared in court on 24 charges that include attempting to sell President Barack Obama's vacant Senate seat.
Mr Blagojevich denies all the charges, which include racketeering, wire fraud, attempted extortion and bribery.
He was arrested 18 months ago along with his brother and co-defendant, Robert Blagojevich.
The trial begins with jury selection.
Mr Blagojevich smiled for a gaggle of journalists as he arrived at the Chicago federal court with his wife, Patti.
"I feel great," he said, hugging supporters who had flocked to greet him. "The truth shall set you free."
A group of elderly female supporters had gathered outside the court with placards, one of which read: "Rod's not cuckoo. Rod's not guilty."
Predecessor in prison
Mr Blagojevich, who intends to take the witness stand, wants the court to hear 500 hours of taped phone conversations to prove his innocence.
Prosecutors say that in the conversations, recorded by the FBI, he attempted to sell or trade Mr Obama's seat.
Other corruption charges relate to demanding donations from potential campaign contributors in exchange for favours.
Mr Blagojevich, a 53-year-old Democrat who was twice elected as governor, was impeached last year. He has vehemently protested his innocence.
If convicted, he could be sentenced to 415 years in prison and ordered to pay fines of $6m (£4.1m).
His predecessor as Illinois governor, Republican George Ryan, was convicted of racketeering and wire fraud and is now serving a six-and-a-half year sentence.