SEEKING ADVANTAGE in the incipient general election campaign, both President Trump and presumptive Democratic nominee Joe Biden have seized on an easy and sleazy stratagem: accusing the other of being a stooge for Communist China. The Trump campaign is promoting the hashtag #BeijingBiden while contending that the former vice president has a record of softness on the regime of Xi Jinping. Mr. Biden and a super PAC supporting him responded with a nasty pair of ads claiming that Mr. Trump “rolled over for the Chinese” during the coronavirus pandemic and “sent China our [medical] supplies.”

Demagoguery about China is hardly new to presidential campaigns, but the latest rhetoric is particularly irresponsible, coming as it does in the midst of the pandemic. It portrays China, and Chinese people, as enemies at a time when Asian Americans are already being subjected to unconscionable attacks, and it could complicate cooperation with China that will be necessary to defeat the novel coronavirus.

As we have written, there should be no question that China’s government contributed to the global spread of the coronavirus by covering up initial reports about it, or that it has tried to use the pandemic to advance its authoritarian political model globally at the expense of democracy. The Xi regime must be pushed for greater transparency, and its propaganda should be rejected. But this is no time to launch into a new Cold War with China, or to blame “the Chinese” for the spread of covid-19 cases across the United States.

On the contrary, it will be necessary for the U.S. president — either Mr. Trump or Mr. Biden — to keep open lines of communication and possibilities for cooperation with Mr. Xi and the superpower he leads. That applies to defeating the virus, since China is the source of much of the world’s supply of medical equipment and could be the originator or manufacturer of a vaccine.

Ironically, Mr. Trump and Mr. Biden are tarring each other for what might be described as past responsible behavior toward China. The Trump campaign blames Mr. Biden for his articulation of what, for decades, was the bipartisan U.S. view that the peaceful rise of China should be welcomed, along with free trade with Beijing. Though the mounting belligerence of Mr. Xi’s foreign policy has raised questions about those policies, treating China as an enemy would invite a disastrous escalation of international tensions.

Mr. Biden, for his part, is vilifying Mr. Trump for making diplomatic statements about Mr. Xi at the outset of the pandemic. Worse, his ad portrays Mr. Trump as submitting to “the Chinese,” as opposed to Mr. Xi’s government, a formulation that more than one observer has described as racist and possibly harmful to Asian Americans. The ad by the pro-Biden American Bridge 21st Century PAC claims that “Trump . . . sent China our supplies”; in fact, the State Department only facilitated the delivery of donations by private charities — and China has since shipped many tons of supplies to U.S. hot spots.

Mr. Trump and Mr. Biden ought to have a serious debate about how to manage the challenge the Xi regime poses. The sort of smears in which they are now trafficking will only make it harder for either of them to find support for responsible policies.

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