Internally displaced people who fled Raqqa city stand near tents in a camp in Ain Issa, north of Raqqa, Syria on April 3, 2017. [Photo/Agencies]

The Pulitzer Prize, which was awarded this Monday, recognizes journalists' excellent work in questioning and investigation. It put into sharp contrast the lack of quality reporting on Syria by the US mainstream news outlets.

The April 4 chemical weapons attack in Syria which killed civilians, including children, was shocking. The perpetrators, whoever they were, should be identified and punished.

Yet before any investigation could even be carried out, the US government decided unilaterally it was the Syrian government army that launched the attack. US President Donald Trump ordered an airstrike on the Syrian al-Shayrat air force base. Besides destroying military jets, the air defense system and other logistical facilities, the bombing killed and injured a number of civilians.

In the past week, the US mainstream media has mostly focused on Trump's U-turn in his Syria policy, or whether it means another Iraq type of war. Few have asked whether it was the Syrian government army or the opposition army that used the chemical weapons or whether the US airstrike violated international law.

It reminds many of the situation in 2003 when then US secretary of state Colin Powell went to the United Nations to make a case for invading Iraq. The argument was later found to be based on false evidence.

Although they were sharply critical later, the unquestioning US news media at that time has been widely viewed as strengthening the credibility of Powell.

According to a University of Maryland study, 57 percent of US mainstream media viewers at the time believed Iraq supported al-Qaida and was directly involved in the Sept 11 attacks on the US in 2001. And 69 percent believed that Saddam Hussein was personally involved in the 9/11 attacks.

None of these was true.

This time, US mainstream news outlets, except the public service network C-SPAN, did not even cover the heated debate at the emergency meeting on Syria at the UN Security Council on April 7, where diverse views were presented.

For example, Bolivian ambassador to the UN Sacha Llorenti, holding an enlarged photo of Powell in his 2003 presentation at the UN, said the alleged weapon of mass destruction was never found. Sweden's ambassador to the UN Olof Skoog claimed the US missile strike "raises questions of compatibility with international law."

Under international laws, such an airstrike on a country would require the mandate of the UN Security Council unless the US was acting in self-defense.

It was not just the mainstream media. Opinion leaders in major US think tanks did not question the strike much either. Except for the libertarian Cato Institute, few raised any questions about the legality of the airstrike. Of the five Brookings Institution scholars who posted their comments on the institute's website after the US attack, only one, Chuck Call, raised the issue, saying "the act reflects a disregard for multilateral organizations and approaches, and its international legal basis remains unclear".

Charlie Savage of The New York Times was probably one of the few US journalists to delve into the legality issue. His lengthy article on Friday called the air strike into question under both international and domestic laws.

As nations make their stances known, one obvious question that should be raised is how some countries can support the US airstrike at the same time they are pushing for an international investigation. If you support the launch of 59 Tomahawk missiles as a punishment for the Syrian government, you must be certain who was the perpetrator. But when you support an investigation, it means that you are not absolutely sure who actually used the chemical weapons.

I have not heard such a basic question raised by US mainstream media.

The author is deputy editor of China Daily USA. chenweihua@chinadailyusa.com