For matters of importance, there’s almost always what could be called an “acid test.”

The phrase comes from ancient times. When a mineral was presented as pure gold, nitric acid was applied. If there was no chemical reaction, the claim of purity was verified.

In less ancient times, on June 12, 1987, President Ronald Reagan was in Berlin to make a speech on that city’s 750th birthday. He spoke near the famed Berlin Wall, erected by Soviets as a physical barrier to divide the city into a half under the control of a democratic German government and a half under control from Moscow.

Mikhail Gorbachev, then secretary of the Communist Party of the Soviet Union, was making noises about increasing the freedoms allowed to Russians and to the many other nationalities in the Soviet Bloc. Reagan offered an acid test with the words, “Mr. Gorbachev, tear down this wall.” Gorbachev let that happen, and the Soviet Union is no more.

The acid test for change in how health services are organized, delivered and paid for in America — specifically whether there’s a public option — is similarly simple and straightforward: When members of Congress agree that whatever they ordain for every person in the United States is applicable to them, too, we’ll know it’s a good idea. No perks. No moving to the head of the line. If they’re willing to get what the people get and pay what the people pay, in proportion, there should be no outcry from the citizenry.

Some in the House and Senate would likely have no problem with this arrangement. They compose the minority who have not assumed the arrogance of superiority that has been so evident in most discussions to date.

Objectively speaking, if there is a public plan it will, over time, displace any and all characteristics — good and bad — of private, competitive health care and health insurance companies.

When members of Congress admit this and signal their willingness to have a government agency decide when, where, from whom and which medical services they will receive, then the acid test will have passed.

Until then, there’s good reason to remain skeptical of their claims of purity.