Donald Trump, accompanied by, from left, Donald Trump Jr., Eric Trump, Melania Trump, Tiffany Trump and Ivanka Trump, at the grand opening of the Trump International Hotel in Washington in October. (Jabin Botsford/The Washington Post)

For the past two days, Trump adviser and son-in-law Jared Kushner has met with Senate and House investigators in closed-door sessions on Capitol Hill. Kushner was there to discuss his meetings with various foreign officials (some referenced in his security filings, some initially not).

A lot of the media attention has been focused on whether Kushner did anything wrong.

But that misses a bigger point. Kushner’s very presence points to what critics call a troubling trend in the Trump administration: a tendency to rely on friends and family for policy advice and action. Political scientists who study the world have a term for this: sultanism, or nepotism. And they say it’s bad not just because it’s unfair but also because nepotism leads to corruption and the erosion of the rule of law.

Here’s why: In a robust, well-functioning democracy, there are many checks against the abuse of power. There are institutions that establish procedures to regulate decision-making and set limits. These institutions are run by people loyal not to any particular leader, but rather to the rule of law itself. They understand, in theory, that their job is to protect the citizens and the constitution, not their bosses.

When leaders rely on their friends and relatives to take key jobs, they can subvert the power of institutions because those people (who often aren’t experts coming into a position with a particular set of objectives) aren’t loyal to the institution. They’re loyal to the person in power. Nepotism “allows presidents to prioritize loyalty and subservience,” Henry Carey, a political science professor at Georgia State University, wrote to me in an email. That also means that when laws are broken by the leader, those loyal “have to compensate the latter by looking the other way on corruption, often combined with plausible denial from below and denial syndromes from above,” he said.

There’s another, longer-term danger, too. In some countries, leaders use nepotism to appoint their children and spouses to top jobs or as successors. In those cases, the regime itself becomes institutionalized, replacing the regulations and rules. In those cases, he explained, “the incentives and temptations for corruption become pervasive.”

In authoritarian regimes, that allows a corrupt family to stay in power for years or decades. In democracies, Carey wrote, “elected leaders rotate but the deterioration of the rule of law erodes steadily and corruption consequently increases steadily.”

There are lots of places where the link between nepotism and corruption is painfully clear. In South Korea, President Park Geun-hye was removed from office in March in a corruption scandal involving a close family friend and adviser.

In Azerbaijan, President Ilham Aliyev (who inherited his job from his father) appointed his wife as vice president. His children have enriched themselves through their leadership in various state-run businesses, some vaguely disclosed, most not. The country has one of the world’s lowest transparency ratings, according to Transparency International, and corruption is endemic to the way the government is run.

In India, where the Nehru-Gandhi family has held some kind of power for nearly as long as the country has been independent, political dynasties are common on the national and local level. More than a fifth of all elected officials are relatives of someone else in office. Corruption is “crippling all the organs of state and reaching into its highest offices,” former Indian finance minister Jaswant Singh wrote on Al Jazeera’s website.

What these regimes have in common, Alfred Stepan of Columbia University and the late Juan J. Linz of Yale University explained, is “unrestrained personal rulership … unconstrained by ideology, rational-legal norms, or any balance of power.”

Other American presidents have sometimes shown similar impulses. President John F. Kennedy appointed his younger brother Robert as attorney general; it’s often said that he was also his closest adviser. (Robert Kennedy also helped cover up his brother’s more tawdry behavior with women.) In response, Congress passed the Anti-Nepotism Statute, nicknamed the “Bobby Kennedy law,” which made it illegal to appoint close relatives to official positions. President Bill Clinton rather famously relied on his wife, Hillary, to navigate his efforts to pass health-care reform — an unsuccessful effort. President George W. Bush relied heavily on Cabinet members who had also served his father.

Trump, who swept into office as an outsider with no government experience, has largely surrounded himself with people who are also light on government experience but heavy on personal loyalty. As Carey said in a piece in The Conversation:

The U.S. presidency has always been prone to sultanistic tendencies, but under a Trump presidency what were once isolated incidents have predictably become a way of governing. When the closest advisers, both institutional (like Ivanka and Kushner) and informal (in the case of his two adult sons), are dominated by family members, the decision-making process will not only be erratic and possibly influenced by private family interests but also tend to ignore legal procedures that have also met the test of time.

Instead of a “team of rivals” under the rule of law, the Trump presidency may be akin to a medieval monarchy, with decisions made by court politics, not legal procedures.