The Littleton High School junior suspended for posting mocking comments about his school on MySpace.com is now back in class.

The American Civil Liberties Union argued that 16-year-old Bryan Lopez's personal Web page postings were protected by the First Amendment.

The ACLU threatened to sue the school, but administrators agreed Monday evening to readmit the teen, averting a federal lawsuit that was going to be filed Tuesday morning.

Lopez ended up missing six days of school -- nine days less than what the school gave him.

"I am pleased that Littleton school officials were willing to resolve this dispute without a lawsuit," said Hugh Gottschalk, an ACLU cooperating attorney whose firm worked over the weekend on the student's case. "A student's right of expression is protected by the First Amendment. School authorities have some ability to regulate students' expressive activities on school grounds and at school-related functions. But school authorities do not have the right to impose discipline for statements that students make off-campus, especially when, as in this case, those statements do not cause any material disruption of the educational process."

ACLU attorneys argued that Lopez used his home computer to post satirical commentary and it was not accessible from any school computers because the school's Internet filters block access to MySpace.com. Also, the posting was not accessible to the general public because it was available only to friends that were given a password, the ACLU argued.

"Apparently one of Mr. Lopez's classmates accessed the Web site, copied the commentary, and then reposted it on his own Web site," ACLU's legal director, Mark Silverstein, said.

A couple of days later, Littleton High School administrators obtained a copy of the posting, which talked about the poor physical condition of the school, the behavior and demographics of students and staff, the perceived racial biases of teachers and administrators, and the poor quality of the resources available to students.

On Feb. 10, the school suspended him for five days on the basis of a school policy that forbids students from engaging in conduct, either on campus or off-campus, "that is detrimental to the welfare or safety of other students or district employees."

The school superintendent then added an additional 10 days to the suspension to give administrators additional time to decide whether to begin proceedings to expel Lopez from school.