Gordon Sondland, the U.S. ambassador to the European Union, recently gave testimony about his role in the Ukraine scandal. Sondland was not someone whose work experience obviously seemed to fit him for the job: He is a hotel magnate. However, he did give $1 million to Donald Trump’s inaugural committee. It is not unusual for presidents to reserve the swankiest ambassadorial posts for rich donors, but Trump has done this more than any other recent president. Ryan Scoville is associate professor of law at University of Marquette, and the author of a recent research paper that shows how this has changed over time. I asked him about what he had found.

HF: In the Democratic primary debates, Elizabeth Warren condemned U.S. presidents’ practice of giving choice ambassadorships to big donors. Has this practice become more or less common over the last few decades?

RS: Political appointments have become more common, but only recently. From Truman all the way through Obama, the norm was to allocate roughly 30 percent of ambassadorships to political appointees and 70 percent to career appointees. So far under President Trump, however, political appointees have filled 44 percent of ambassadorships. This is the highest percentage since FDR.

HF: Are the political appointees of recent years any different from their predecessors?

RS: Over the past 40 years, the qualifications of the average political appointee have gradually eroded. In comparing political appointees under Trump and Reagan, for example, one finds that Trump’s are inferior in terms of language abilities, prior experience in the receiving state and region, prior experience in foreign policy and prior experience in organizational leadership. Over this same 40-year period, campaign contributions from political appointees have shot up dramatically in value, to the point where the average contribution under the first two years of Trump was nearly 1,400 percent larger than the average contribution under Reagan, even after adjusting for inflation. The co-occurrence of these two developments (eroding credentials and skyrocketing contributions) raises questions about whether they are causally related. If they are, and if credentials predict performance, then it could very well be the case that the imperatives of campaign finance are generating an increasingly deleterious effect on the ability of the United States to conduct foreign relations.

HF: Do big donors prefer some kinds of ambassadorships over others?

RS: Since at least the early 1980s, big donors have overwhelmingly served in countries that are popular destinations for global tourism. Thus, nearly all U.S. ambassadors to places such as Japan, Norway, France and Italy have been political appointees, while virtually all ambassadors to most states in Africa and Southeast Asia have been career officers in the Foreign Service.

HF: Does your research shed light on whether people who pay for ambassadorships are better or worse at the job than people who don’t pay?

RS: My research shows that donor nominees are generally far less qualified than career nominees under a number of metrics that are commonly accepted as relevant, such as prior experience in foreign policy. If those metrics reliably predict performance in office, then donors are less effective than their career diplomats. Unfortunately, there is very little social science on the correlation between credentials and performance in this area. One study found that the performance scores of political appointees to ambassadorships are roughly 10 percent lower than the scores of career appointees, but additional research is needed.

HF: Why have previous legal efforts to cut the relationship between donations and ambassadorships not worked?

RS: In the past, some commentators opposed legislative attempts to regulate ambassadorial qualifications on the ground that the Appointments Clause guarantees the president unfettered discretion over nominations. That position is contestable, but some members of Congress embraced it in the past. In addition, and probably more importantly, it has been common for political appointees also to donate significant sums of money to the election campaigns of members of the House and the Senate. Members have little incentive to adopt legislation or pursue other measures against their own donors.