ISTANBUL, Turkey — One of Turkey’s leading authors was acquitted yesterday of “insulting Turkishness” — a crime Western-looking Turks view as an embarrassment and one of the biggest obstacles to joining the European Union.

The speedy court decision was seen as a step toward securing greater freedom of speech, but critics said until the law is abolished, Turkey would remain a place where authors are regularly put on trial.

“The fact remains that [Turkey’s courts] established a restrictive interpretation of Article 301 of the penal code which is not in line with the European Court of Human Rights and European standards of freedom of expression,” an E.U. spokeswoman, Krisztina Nagy, warned after the decision.

But the government is reluctant to change the law — which makes it a crime to insult Turkey, “Turkishness” or the government — because it has broad nationalist support.

E.U. officials counter the real damage to Turkey’s image comes from putting writers like Elif Shafak on trial — a case brought by nationalist lawyers because of words spoken by the novelist’s fictional characters.

The court ruled to acquit about an hour-and-a-half into the trial on the grounds there was “no evidence” that Mrs. Shafak had insulted Turkishness.

“I hope that the absurdity of this case — we’re talking about fictional characters — will encourage people that it’s time to act,” a senior European Parliament member who attended the trial and is a vocal supporter of Turkey’s E.U. bid, Joost Lagendijk, said.

Mr. Lagendijk called on Turkey’s pro-E.U. Prime Minister Recep Tayyip Erdogan, who has himself spent time in jail for reciting an Islamist poem in 1999, to intervene and change the law.

“Each court case that is started is a victory for those who don’t want Turkey in the E.U., and a defeat for me and those in the E.U. who are in favor of Turkey’s accession,” Mr. Lagendijk said.

But nationalist lawyers said they will continue to bring legal action against anyone who insults Turkey and vowed to appeal the Mrs. Shafak decision.

Fiercely opposed to Turkey joining the E.U. and hostile to any foreign intervention, the lawyers spent most of the trial trying to eject non-Turkish observers — especially Mr. Lagendijk — from the packed Istanbul courtroom.

“This is not a consulate court!” one of them yelled minutes after the case began.

“Let the foreigners go to hell! They can supervise their own country!” bellowed lawyer Fuat Turgut as he pushed his way through a crowd in the doorway.

The lawyers were repeatedly rebuffed and they eventually left the courtroom in protest, after which the judge moved quickly to acquit Mrs. Shafak.

“The court concluded in a 1 1/2-hour session that there was insufficient evidence to suggest that she committed a crime,” Judge Irfan Adil Uncu said.

Mr. Erdogan said he was pleased with the acquittal and said Turkey was open to discussing Article 301. But in implicit support of the intent behind the law, he added: “Criticism is one thing, insulting is another.”

Justice Minister Cemil Cicek made similar remarks this week, asking a journalist for the Turkish Daily News whether he was willing to “let people curse at Turkey, insult Turkishness and get away with it.”

Mr. Erdogan regularly files lawsuits over alleged personal insults, and on Wednesday was awarded $3,400 in a case against a journalist who suggested the prime minister might be mentally ill.

Mrs. Shafak, 35, gave birth on Saturday and was at a hospital in Istanbul and did not attend yesterday’s trial. If convicted, she could have received a maximum three-year prison sentence.

Mrs. Shafak’s husband Eyup Can, editor-in-chief of the Turkish newspaper Referans, said he hoped the decision would be a model for future cases, and pushed for the abolition of Article 301.

“For the judge to make this decision in the first hearing is an important step,” Mr. Can said as he was congratulated by friends after the trial. “But the most painful thing is that Turkey has become famous as a country that tries writers.”

In a sign public opinion may be turning in favor of change, nationalist protesters outside the courtroom — usually a rowdy, often violent group — were shouted down by other spectators.

Mrs. Shafak’s book, “The Bastard of Istanbul,” was released in Turkey on March 8 and has sold more than 50,000 copies. The court case was brought for words spoken by fictional Armenian characters regarding one of the most disputed episodes of Turkey’s history, the mass killings of Armenians during the final years of the Ottoman Empire.