John Tomkins, 46, is acting as his own attorney, which means he would have to question himself on the stand. The suspect admits to writing threatening letters but says nobody was ever at risk.
"I did not design these devices to be destructive," he said.
Federal prosecutors rested their case Wednesday after presenting two days of evidence. They say Tomkins was dubbed the "bishop bomber" and mailed letters to investment offices trying to manipulate the prices of stocks he opened.
"You're representing the government, and you want to make sure that the government is not trampling on individuals' rights," said former prosecutor John Muldoon.
The former machinist and letter carrier struggled at trial with the rules of criminal procedure, with the judge and prosecutor at times seeming to offer assistance.
"Even though you want to win, this is a criminal case, you have to be cognizant of the defendant's constitutional rights. You don't want him to unknowingly waive some. You don't want to take advantage of him and then have a right violated that later comes back and returns the case on appeal," Muldoon said.
Tomkins admitted to the jury he mailed the letters but insisted the bombs were never wired to explode. He called his two brothers and one other witness as a character witness. In response, the brothers testified that he was a peaceful person who enjoyed a good childhood.
Tomkins faces 13 criminal counts for mailing threatening letters and sending those pipe bombs. The government says some of those packages included notes that said, "Bang, you're dead."
The judge ruled Tomkins cannot testify about his medication for depression because he was not on the medication at the time of the crime. Tomkins' attorney and wife had no comment.