The novel coronavirus is not an ideal biological warfare agent, experts say, because its impact on the United States and adversaries alike cannot be controlled. But China refuses to help the world answer questions about its origin.

“Coronavirus would be a bad candidate to be a bioweapon,” said Thomas Spoehr, head of the Center for National Defense at the Heritage Foundation, who was the U.S. Army’s senior-most officer for chemical and biological weapons during his 36-year military career.