Doctors, lawyers and soldiers have to prove that they’re mentally competent to do their jobs. Should the president?

That’s what Rep. Brendan Boyle, a Pennsylvania Democrat, proposed on Tuesday, when he introduced a bill that would require the president-elect to pass a physical and mental medical examination before swearing in. Although written to broadly encompass anyone elected to the nation’s highest office, the bill is clearly aimed at President Trump. It’s even named after one of the president’s recent tweets: the Standardizing Testing and Accountability Before Large Elections Giving Electors Necessary Information for Unobstructed Selection Act. (That’s STABLE GENIUS in acronymese.)

Trump’s mental health has been the talk of Washington for more than a year — mental health professionals have offered long-distance personality evaluations, there have been suggestions that Congress could invoke the 25th Amendment, and the public has debated whether the president shows signs of age-related cognitive decline. But the conversation reached fever pitch this past week after the publication of Michael Wolff’s book “Fire and Fury: Inside the Trump White House.”

We are not here to adjudicate whether Trump is mentally ill, suffering from dementia or otherwise mentally incapacitated. (We do, though, have thoughts about whether it’s appropriate to discuss the matter.) Instead, we’re seeking to better understand whether it’s practical to screen a president for mental competency. For answers, we turned to law, medicine and the military — other industries where a person’s personal stability can have big impacts on the safety of others. Sure enough, evaluations like the one proposed by Boyle are done routinely in some of these other professions. But comparing how mental health is handled in these different jobs also demonstrates why transferring other industries’ norms wouldn’t be easy — or even desirable.

There are tests for mental competency before someone can become a doctor, a lawyer or a soldier. The specifics vary by state for lawyers and by specialty for medicine and the military.

All of them are broad entrance examinations, focused on whether a potential lawyer, doctor or soldier can do the job that they are proposing to take on. For example, to become a lawyer in Illinois, you have to pass a character and fitness review. Applicants fill out documents, including character references and medical history questionnaires, which are reviewed by five different committees, said Jayne Reardon, executive director of the Illinois Supreme Court Commission on Professionalism. If those committees think an applicant needs additional scrutiny, they can choose to hold a hearing. “It can be an adversarial process where the applicant gets a lawyer to represent them,” she said.

And that process doesn’t end once you’re part of the club. Surgeons, for instance, undergo a review every two years by whatever hospital they are credentialed to work at, which basically serves as a broad professional check-up, said David Welsh, a surgeon and a member of the board of governors of the American College of Surgeons. Meanwhile, drill instructors in the military get mental health-specific evaluations annually because their jobs are so psychologically demanding, said Craig Bryan, a psychologist and executive director of the National Center for Veterans Studies at the University of Utah.

Though the specifics of these institutional systems vary, there are a few similarities that could help shape a hypothetical presidential screening. First, all three professions are focused on behavior and potential performance on the job, not on whether someone has been diagnosed with a mental illness or personality disorder, or has reached a specific age. Someone with bipolar disorder, for instance, could still pass the fitness reviews Reardon described and become a lawyer — although, depending on their personal medical history, they might end up with a conditional license that requires them to keep taking their prescribed medication to remain one.

All these testing systems are also universally applied. While some individuals might end up receiving a higher-than-normal level of scrutiny, there’s a basic level of testing that everybody in these professions has to take. Everyone is treated the same. No one is assumed to be A-OK and given a free pass.

“It’s a very delicate balance because (people with mental health issues) have rights too,” Reardon said. “But their rights end where the clients are not being protected.”

This balance is thought about a little differently in the corporate world, where it’s common to use tests of personality to screen people for jobs. But that’s usually implemented on a company-by-company basis, said Jeffrey Sonnenfeld, a dean of leadership practice at the Yale School of Management.

There’s no universal entrance examination that licenses people to become corporate executives or members or a board of directors. And while Sonnenfeld said that can create risks, he was also opposed to implementing something like the universal screenings used in law, medicine and the military. The corporate world has relied, to varying degrees, on personality and mental competency tests as a filter in hiring and promotions for decades. But those tests have often proven to be scientifically flawed and bad for corporate culture. “In France they have handwriting analysis and even had phrenology in use until quite recently,” Sonnenfeld said. Neither of those systems is a scientifically valid way of learning about human personality and behavior. Meanwhile, the personality tests commonly used by U.S. companies can end up accidentally incentivizing a conformist workplace or scientifically enforcing discrimination against minorities and people with disabilities.

Regardless of the test, the interpretation of the results is just as important as the way they’re gathered. These concerns — whether the metrics being employed to test someone’s mental competency are valid and whether the results are being interpreted in a way that is both fair for individuals and good for the institution — were shared by Elizabeth Suhay, a professor of government at American University whose work involves the interactions between science and politics. She was troubled by the idea of instituting a competency test for the presidency, especially in a polarized political climate. “It’s becoming pretty obvious to everybody that people are able to politicize facts just as much as values,” Suhay said.

She drew a corollary to the impeachment process, which effectively allows Congress to define what counts as “high crimes and misdemeanors.” Impeachment is an open, democratic process, Suhay said. But it leaves a lot of room for politicization in the definition of what is a problem and what isn’t. A mental competency test for the presidency would likely do the same. But because it would come with a veneer of science, in the form of test results, it could carry a false sense of certainty and objectivity.

But the stakes are high, she said. If you make the presidency dependent on passing a mental health test of some sort, you could end up undermining the foundations of democracy as people find ways to use the test to prevent opponents from running. At the same time, most voters don’t have transparent information about a candidate’s mental health. Both the risks to democracy and the risks of an incompetent president are real.