Fierce debate over who deserves to be an immigrant to the United States has drawn on for decades.

Recently, President Donald Trump and hardliner Republicans have proposed overhauling the U.S. immigration system to focus principally on “merit-based” immigration. As they define it, merit means being highly educated, fluent in English, relatively wealthy and having a job awaiting in the U.S.

Meanwhile, advocates of legal status for Dreamers – immigrants brought to the U.S. as children without authorization – argue that these individuals are particularly deserving of protection, while refugee organizations underscore the dire situation of asylum seekers.

The lure of “merit” is clear: When choosing individuals for some reward, it may seem natural to prefer those who can claim to deserve it most. The concept of merit undergirds many aspects of everyday life: university admission practices, civil service hiring, police and firefighters’ examinations, sports teams’ tryouts and musical competitions.

However, as I discuss in my book “The Measure of Merit,” rewarding the “best” has often helped justify treating people unequally. My research shows that ways of assessing merit are rarely neutral, and that questions of fairness arise when individuals or groups feel they have not received the same opportunities as others.

Equality and merit

The use of merit to justify inequality has a long history in America. From the republic’s founding, Thomas Jefferson’s ringing declaration that “all men are created equal” was balanced against the widespread belief that some people, whether because of birth or education or both, were more talented than others. These individuals, Jefferson and others argued, ought to be afforded greater opportunities, whether for advanced education or political leadership.

Jefferson celebrated the “natural aristocracy,” and James Madison and Alexander Hamilton argued that indirect election of senators and the president would help ensure that only the most meritorious would rise to positions of political leadership. Merit, in fact, proved a powerful way of allowing one to embrace equality and yet still justify often profound differences in opportunity. Thus, at the nation’s founding, women, African-Americans, Native Americans, noncitizen “aliens” and non-property-holding males were excluded from full political and civil rights.

Resistance was swift to the dominance of a privileged few, and slowly these basic rights were extended, first to white working-class males, then African-American men and finally women. However, there are still many circumstances where merit is employed as a way of unequally doling out limited resources. In these instances, it is crucial to ask two questions: Why turn to merit to choose some individuals over others, and how exactly will merit be gauged?

Complicating merit

Merit is least controversial when the criteria for success are clear and the reward is appropriate. For example, few would protest that spots on the national Olympic track team go to the top finishers in an Olympic trial. There is only one measure of success – speed – and the Olympics seek a nation’s best at that event.

Even in this case, however, some might question relying on a single trial rather than, say, all races run in the preceding six months or year. Merit can be tricky no matter how clear-cut the criteria.

When the task itself is complex, ranking performance becomes harder. There are also often real questions about whether small differences in performance matter beyond a certain level of proficiency.

For example, what attributes are required to be a good firefighter? Strength, speed, agility, courage, fortitude, intelligence – and the list could go on. So, should only the strongest or most courageous applicants be chosen? Or would choosing from a pool consisting of all those who are strong, fast, smart and brave enough to perform a firefighter’s duties be better? Which approach will promote both competence and diversity? Merit can be an effective way to make choices, but also, as my book shows, a powerful means of rationalizing biases and rendering them difficult to see.

Immigration and racial exclusion

For almost a century, the United States had a relatively open immigration policy. Millions of Irish, Germans, Scots and Scandinavians, among others, emigrated to the U.S. in the wake of economic upheavals and political repression in their home countries.

However, starting in the 1880s, the government began to consider immigration restriction legislation, first with the Chinese Exclusion Act of 1882 and culminating in 1924 with the Immigration Act.

Merit was rarely explicitly mentioned as the rationale for preferring some groups over others. Nonetheless, the push to exclude Asians and then Eastern and Southern Europeans – mostly Catholics and Jews – echoed the period’s ethnocentrism and infatuation with eugenics. Lawmakers viewed some “peoples” – primarily Northern Europeans – as biologically and culturally “superior.” Restriction proponents argued that immigration should privilege these “superior” individuals.

Similarly, policymakers today must examine the use of merit to determine how it privileges certain groups and individuals at the expense of others.

What truly are the important attributes desired of a legal immigrant? Money? Advanced education? Good character? Willingness to do labor native-borns will not? Family ties?

How we answer depends on what goals we want to accomplish and values we wish to represent. Do we reward solely those who are already prospering? Or perhaps we should enact an immigration policy that also reflects the founding creed, that all people “are created equal.”

John Carson received funding for some of this research from the National Science Foundation, Wellcome Trust, and National Humanities Center.