The two brothers are on trial simultaneously.
With some of his trusted lieutenants leaving, and campaign donations markedly slowing, Rod Blagojevich turned to his older brother for help.
In summer 2008, businessman Robert Blagojevich, a lifelong Republican and retired military man, came to manage the then-Governor's campaign fund.
Within months, Robert Blagojevich would find himself in what he calls "the battle of his life."
He comes and goes quietly from court. He doesn't encourage autograph seekers, pose for pictures or make pronouncements.
He sits at a separate defense table and, from the appearance of it, has little if any interaction with his younger brother.
"This is the battle of my life and I'm prepared to confront it," said Robert Blagojevich.
Robert Blagojevich, a retired Army lieutenant colonel, is confronting charges of wire fraud, extortion conspiracy, attempted extortion and bribery conspiracy. Three of those counts have to do with the alleged sale of the Senate seat, and they are built in part on a phone conversation between Robert and Rod five days before the then-governor's arrest.
Witnesses have testified that supporters of Jesse Jackson, Jr., were going to raise big money for Rod Blagojevich if he named Jackson as Senator, and Rod tells Robert to set up the meeting.
Rod Blagojevich: "So, you know, we, if, if in fact there's there's, this is, you know, this is possible, then some of the stuff's gotta start happening now."
Robert Blago: Yep
Rod: "Right now"
Robert: "Very good"
Rod: "And we gotta see it."
Rod: "You understand? Now you gotta be careful how you express that. And assume everybody's listening, the whole world's listening."
Rod: You hear me?
Robert: "Right, right, right."
Robert sets up the meeting with fundraiser Ragghu Nayek, and then later cancels it - at his brother's direction.
Prosecutors argue that that and other conversations make Robert a part of the conspiracy.
"I'm psychologically and physically prepared to take those people who claim that I've done something wrong," said Robert Blagojevich outside court.
After the defense begins its case next week, at some point Robert Blagojevich will take the stand and testify in his own defense.
In a case loaded with tapes of his brother's salty-language-filled deal talking, Robert is heard far less often, and frequently sounds like a voice of reason, like in an exchange in which Rod says he may name a deputy governor to the Senate seat, and then name himself to succeed her.
Robert: "So, what, come July when they're impeaching you, you step down and...
Robert: I take your ...
Robert: "...oh, Jesus, that's ugly
Rod: Why is that ugly?
Robert: Oh, it's self evident. I don't have to explain it.
Rod: What are you nuts? What's uglier? That, or being impeached?
Robert: Neither one. Neither one. I mean, it's so, it's so transparent.
The defense teams for both Robert and Rod Blagojevich have their own selected conversations from the government tapes that they want to present in court.
The judge will likely decide next week on what'll be allowed in.
There is always some risk when a defendant testifies, but Robert Blagojevich says he will do so, because he did nothing wrong.
His brother has said the same.