Give a dog a bad name and hang it. That is exactly what the United States was trying to do when it pointed an accusing finger at China on Wednesday, claiming that the country was behind the massive hacking of data from hotel giant Marriott, involving some 500 million of its customers.

Yet instead of concrete and credible evidence, such a serious accusation has so far been based on nothing other than "we believe" and "we suspect" — perfunctory assumptions — as made when US Secretary of State Mike Pompeo told a Fox News program that Washington believes China masterminded the Marriott data theft, and when officials from the Justice Department, the FBI and the Department of Homeland Security told the Senate Committee on the Judiciary that China is working to steal trade secrets and intellectual property from US companies in order to harm its economy.

An investigation is now under way into the Marriott data theft, but given how arduous and complicated it could be — since the hacking is known to date back to 2014 at least — such presumption of guilt can only be politically motivated.

Since Pompeo's allegation came amid rising tensions between the two countries over trade frictions, people can't help but wonder whether the US is up to its tricks again as it seeks to gain an upper hand in the deadlined negotiations aimed at reaching a deal with China.

The unfounded accusation is especially disappointing and worrisome since both countries had previously reached a consensus that they would not knowingly support the cyber theft of corporate secrets or business information, paving the way for concerted efforts to tackle cybercrimes.

There were doubts at the time about whether that agreement would have any practical effect on the behavior of the US, and those doubts would appear to have been justified by Pompeo's remarks.

Rather than trying to claim China stole the horse, the US should first fix the stable door. One of the largest ransomware attacks, which was staged in May last year, used one of the hacking tools that the US National Security Agency created for its own use. That an agency tasked with fighting cyberattacks was itself so vulnerable to hackers shows how serious the problem is.

China, as a major target of serious international cyberattacks, has always advocated international cooperation to safeguard cybersecurity. The internet is so pervasive in modern life that only combined efforts can ensure effective protection for all the inhabitants of cyberspace.