In response to a few incidents that Verizon Wireless calls "isolated," a politician is leading an effort to urge the FCC to prevent blocking of text messages.

Along with Public Knowledge, Free Press and others, Assemblyman Richard Brodsky filed a petition against Verizon for allegedly refusing to carry short-code messages for rivals or controversial groups.

Last year, Verizon refused to allow abortion rights group NARAL Pro-Choice to use a short code to reach members who had signed up for text messages, but then reversed its decision amongst media coverage of the incident. Verizon and Alltel also last year allegedly refused to carry short-code messages for the Voice over Internet Protocol company Rebtel.

"The same values that motivated the First Amendment are behind attempts to stop corporations from censoring communications between people," Brodsky said Monday in a conference call with reporters. Brodsky is the same politician championing a bill to regulate online behavioral targeting.

Verizon is asking the FCC to dismiss the petition, arguing not only that the complaints refer to "isolated instances" that don't warrant government involvement, but also that such rules would enable spammers or pornographers to use short codes.

The telephone company reportedly told the FCC that it declines to activate about 5 percent of short code campaign proposals for failing to meet the standards, which it defines as precluding "content that promotes the use of alcohol, tobacco products, guns or other weapons, and illegal drugs" and "restrict profanity, depictions of sexual activities, and violence."

Opponents worry about big corporations' ability to censor content.