AURORA, Colo. -- Aurora, Colo. school officials said that it was the disruption that an 11-year-old's anti-Barack Obama T-shirt sparked - not its political content - that got him suspended from school last week.

But the boy and his father, who designed a shirt that read "Obama -- A terrorist's best friend," said the youngster's free-speech rights were violated when Aurora school officials suspended him for three days. The father said he's considering a lawsuit.

Daxx Dalton was sent home from his sixth-grade classes at Aurora's Frontier School after he refused to either turn the shirt inside out or wear another shirt.

The student and his dad, Dann Dalton, contend school officials would not have disciplined the youngster if the T-shirt had skewered Obama's opponent, Republican John McCain.

"If I said 'McCain is a terrorist's best friend' it wouldn't have gotten me into trouble," the boy said outside the school Tuesday afternoon as he and his father waited to pick up his 10-year-old sister.

However, Aurora Superintendent of Schools John Barry said the sister also donned an anti-Obama T-shirt that she was allowed to wear because she caused no disruption during her classes. Her shirt had the word Obama with a bar through it and a pro-McCain slogan on the back.

"This student was not suspended because of a shirt," Barry said of the boy. "He was suspended because of an issue of disruption."

Barry said Aurora students wear hundreds of shirt designs, including some with political slogans, without any incident. However, that was not the case with Daxx Dalton's shirt.

"It was a problem when it started being disruptive," said Barry, who was at the school that day. "A number of kids came to a number of teachers expressing that they were upset. There was shouting and yelling."

The turmoil spilled over from the school yard to a math class, he said.

"When you have a math class, obviously you don't have political science debates," he said.

Barry said students may have also been sensitive to the word "terrorist" on that day, coming a week after the seventh anniversary of the Sept. 11, 2001, terrorist attacks.

The school's dress code prohibits dress or appearance that "cause or are likely to cause a material and substantial disruption to the educational process or school-related activities."

Dalton was suspended Thursday after wearing the red, white and blue-decorated T-shirt on a day when students were encouraged to wear the patriotic colors in honor of a Vietnam-era military veteran who won the Medal of Honor.

First Lieutenant Brian Thacker with the U.S. Army made stops at Aurora Frontier K-8 and Gateway High School.

Daxx Dalton said his father had the idea for the shirt and did most of the design.

The father, who calls himself a "proud conservative," said: "I'm full of all kinds of anti-Obama cliches" and acknowledged helping his son with a slogan so "he could easily capsulate it on a T-shirt."

Daxx Dalton said the anti-Obama slam was popular with his "Republican" buddies, who gave him a high-five and said: "sweet, dude."

But the younger Dalton also said an African-American classmate shouted that he was a racist on the playground.

"He said: 'You just don't want a black president,'" Dalton recounted.

"I agreed with that because that would be the only thing that made him shut up," Dalton said. "But I'm not racist.

"Yeah, it was a disruptive in the school, but not enough to get suspended," the boy added.