The public health challenge posed by the tens of thousands of Americans shot to death each year wasn’t always the subject of such a toxic partisan divide. There used to be a bit of flexibility between the parties before the gun lobby so relentlessly targeted politicians who dared to consider compromise.

President Ronald Reagan, a Republican and proud member of the National Rifle Association, was celebrated by the gun lobby for steadfastly maintaining his opposition to handgun control even after he was critically wounded in a 1981 assassination attempt that left a bullet “an inch from my heart,” as he noted. After recovery, President Reagan went further and called for the abolition of the Bureau of Alcohol, Tobacco and Firearms, the enforcer of federal gun safety laws.

But once retired from politics, Mr. Reagan, unlike Republican party leaders these days, reconsidered the issue and eventually showed a willingness to embrace reasonable bipartisan proposals to protect the public from gun abusers.

Two years after he left office, Mr. Reagan surprised the nation by endorsing the proposed Brady Law that established federal background checks of firearm buyers for criminal records and histories of mental disturbance. The former president noted that the law was inspired by the case of Jim Brady, his devoted press secretary who was partially paralyzed by a gunshot wound to the head during the assassination attempt. “This nightmare might never have happened” if the Brady Law had been in effect, Mr. Reagan emphasized in an op-ed in The New York Times. His support was significant in the eventual passage of the law in 1991. ...