Abhinya Sawatvarakorn, 19, who faces possible arrest Saturday after being accused of making critical comments on Facebook two years ago, is the latest symbol of the ferocity of feeling around the issue in the deeply divided nation.
Known by her internet alias Kanthoop, the teenager says she has been the victim of a witch hunt that has seen her barred from several universities and publicly vilified.
"I'm afraid I will not receive justice but I'm not afraid to be in jail," she told AFP on the campus of Thammasat University, the only establishment to accept her for study.
Kanthoop, who said the claims against her are based on maliciously edited screen grabs of her comments, wants the law, which carries a penalty of up to 15 years for each count, abolished.
Lese majeste, or article 112 of the Thai criminal code, is designed to protect senior royals from insult, but academics say it has been politicised in recent years.
Many of those charged have been linked to the "Red Shirt" movement, supporters of ousted former Prime Minister Thaksin Shinawatra, and other critics of the previous establishment-backed government.
The number of people charged with the offence has surged since Thaksin was deposed in a 2006 coup, making the law itself increasingly the subject of debate -- even though powerful figures such as the army chief have suggested dissenters should leave the country.
David Streckfuss, an independent academic and expert on lese majeste, said the current public attention to the issue would have been "absolutely unimaginable" last year.
"People are becoming more and more used to debate over the law. The more they see it in the news, the more it's becoming part of the normal talk of the day," he said.
The royal family is an extremely sensitive subject in Thailand, with 84-year-old King Bhumibol Adulyadej revered as a demi-god by many.
There were 122 lese majeste cases sent for prosecution from January to October 2011, which Streckfuss said was in line with the level seen in 2009.
But in 2010, when the country was rocked by deadly anti-government protests by the Red Shirts, there was a spike of 478 cases.
Thai academic Thitinan Pongsudhirak said the measure had left the country gripped by a "climate of fear" and warned reformists can become "radicalised" when debate is shut down.
"It is a self-fulfilling situation -- fear and paranoia which aggravates and begets countervailing moves, which reinforce fear and paranoia," he said.
Recent cases have sparked fierce debates, including over a 61-year-old man who was jailed in November for 20 years for sending text messages deemed insulting to the monarchy.
A US citizen in December was also handed two-and-a-half years in prison for allegedly defaming the king.
Social media websites such as Facebook and Twitter are providing a platform for both critics of the law and ultra-monarchists, who have encouraged Internet users to report posts that could violate lese majeste.
One group of legal academics, known as Nitirat, has drawn particular fire over its calls for amendment of the law. Founder Worachet Pakeerut said he has faced threats, blaming attempts to "create misunderstanding and hatred".
The group is based at Thammasat, long considered a hub of political debate and the site of a bloody crackdown on student protesters in 1976.
Thitinan said some of Nitirat's suggestions, such as making a future king swear an oath to protect the constitution, were "unpalatable to Thai society" -- but added other recommendations including ending the practice whereby anyone can denounce anyone else were "very sensible".
Prime Minister Yingluck Shinawatra said she would not amend the law, despite concerns raised by the US, the EU and United Nations, in an apparent attempt to avoid the accusations of disloyalty levelled at her ousted brother.
But Thitinan said some compromise will have to be reached. "The royalists have to sort out their fallback position now, what concessions they are going to have to make to hold the line, because this line is not going to hold."
Streckfuss said lese majeste has become the "dividing line" in Thai society.
For Kanthoop, that division has torn her family apart -- her sister wished her dead and her royalist father told her to change her name.
"I didn't think it would come to this... But I think I can live on my own and I'm proud of myself. I feel free," she said.