Bangkok , Thailand ( CNN ) -- A Thai criminal court has sentenced a Thai-born American to 2 1/2 years in prison for insulting the monarchy , the latest case involving controversial laws for defaming , insulting or threatening the royal family . Joe W. Gordon , whose Thai name is Lerpong Wichaicommart , cooperated during the investigation of his case and pleaded guilty , resulting in a lenient sentence , his lawyer said . But the charge of writing and posting articles insulting the monarchy under the Southeast Asian country 's lese majeste laws can yield a sentence as high as 20 years in prison in the Buddhist country , where the king is highly revered . `` A chokehold on freedom of expression is being created in the name of protecting the monarchy , '' Brad Adams , Asia director at Human Rights Watch , said in a report published December 2 on the laws . King Bhumibol Adulyadej has pardoned foreigners in similar cases in the past . The lawyer , Anon Rumpa , said he plans to file for a royal pardon . Speaking to reporters after the verdict , Gordon said he was `` an American , not a Thai citizen . '' An `` American has rights and freedom to comment . In Thailand , there is limitation in expressing opinion , '' he said . Gordon , 54 , returned to Thailand last year after 30 years in the United States . He was arrested in May for posting a link on his blog to an unauthorized biography of the king , according to the Asian Human Rights Commission . He has been detained without bail since then . State Department spokesman Mark Toner said the United States regards freedom of expression as a fundamental human right , `` so we are troubled by the outcome of this case '' `` We also have no higher priority , as you have often heard from this podium , than the protection of American citizens abroad , so we are engaged with the Thai authorities and consular officers from our embassy in Bangkok are in touch with Mr. Gordon and his family , '' Toner said Thursday . He said the United States has conveyed its views on the case to Thai authorities and does n't see the incident `` adversely affecting the overall relationship . '' Elizabeth Pratt , consul general at the U.S. Embassy in Bangkok , called the sentence `` too high for just expressing his free speech . '' `` We also respect the law of Thailand . We are trying to help Mr. Gordon in any way that we can . '' The Human Rights Watch report cited a sentencing of a 61-year-old man to 20 years in prison for sending four text messages considered offensive to the queen . It said `` many other harsh punishments '' for violating the laws have been rendered in recent years . `` The severity of penalties being meted out for lese majeste offenses in Thailand is shocking , '' Adams said . `` The new government seems to be responding to questions about its loyalty to the monarchy by filing countless lese majeste charges . '' Human Rights Watch said the government has launched `` a major campaign against alleged violations '' of the laws since Prime Minister Yingluck Shinawatra took power last summer . `` The roots of the recent campaign appear to be found in the September 2006 military coup against Thaksin Shinawatra , the prime minister at the time , who was considered by royalists to be insufficiently loyal to the monarchy , '' the report said . Yingluck Shinawatra is Thaksin 's sister . The rights group said private people and entities `` often misuse '' the laws for political reasons . It has called on Thailand `` to amend the laws so that private parties can not bring complaints of lese majeste since no private harm is incurred . '' `` The heavy-handed enforcement of lese majeste laws has a devastating impact on freedom of expression in Thailand , '' Adams said . `` A broad-based discussion is urgently needed to amend the laws to ensure that they conform with Thailand 's international human rights obligations . ''
NEW : State Department spokesman says U.S. `` troubled '' by case outcome . The Associated Press contributed to this report. Gordon 's guilty plea leads to his lenient sentence , his lawyer says . The king has pardoned foreigners in similar cases in the past .