With just over two months remaining before Inauguration Day, President-elect Donald Trump and his transition team are in the midst of building his Cabinet—which includes the heads of 15 executive departments as well as the attorney general—and making top White House personnel choices. Here, William Mayer, professor of political science and an expert on American presidential elections, examines how presidents select these positions and the significance of their choices.

How does a president go about selecting a Cabinet and senior staff?

I don’t think there’s an easy recipe for doing it. There are many considerations that go into selecting presidential staff and Cabinet members. On the one hand, you want people who are technically competent to do the job—people with previous government experience or who have managed large organizations. The president-elect also looks for people who are ideologically compatible with what he has been saying during the campaign. For example, one suspects that Trump will not appoint a secretary of homeland security who is an advocate for open borders. Personal loyalty or familiarity is another consideration. Republicans who endorsed Trump at an early stage in the race, like Rudolph Giuliani, will certainly be considered for Cabinet positions. These days, there is also emphasis on having diversity in the selections. There is no way Trump could select a staff and Cabinet that doesn’t have a fair number of women in it, and no doubt he will look for major posts to give to Hispanics and African Americans.

We won’t really know about the significance of a lot of Trump’s appointments until many months from now, maybe many years from now.
—Political science professor William Mayer

What is the significance of these selections, and how they can define a president’s priorities?

That varies a lot from president to president. Some presidents give their Cabinet members a fair amount of discretion to pursue policies the way they want to. There are others who make most of the important decisions themselves, and the Cabinet members are basically responsible for carrying out the president’s decisions. This can also vary between a president’s different Cabinet members. It’s difficult to say with any confidence what any particular set of Cabinet appointments means. Frequently, the messages that get read from a president’s appointments turn out to be wrong. For example, George W. Bush selected Colin Powell as his secretary of state. I think it’s fair to say that while that was well received at the time, Powell didn’t have as much influence over the foreign policy of the Bush administration as many people thought he would. He also appointed Christine Todd Whitman as administrator of the Environmental Protection Agency, and I think it’s also fair to say she didn’t have anywhere near as much influence on the administration’s environmental policies as she may have thought they would. So, it’s hard to say. We won’t really know about the significance of a lot of Trump’s appointments until many months from now, maybe many years from now.

Even though the significance may not be known for some time, what do the appointments themselves signal to the public?

You can read some signals about what the president thinks he is trying to do, but it often ends up being very different from what the president actually does once he gets into office. Richard Nixon appointed what he thought was a strong and relatively independent Cabinet, and I think honestly believed that he would give the Cabinet members a fair amount of power. In fact, he, to a remarkable extent, tried to centralize decision-making in the White House. In general, Cabinet appointments are over-interpreted. A newly elected president in general is a bit of a question mark. There’s a great deal of uncertainty about every newly elected president as to what he will do and how he will reconcile conflicting elements within his campaign platform or within his party. The press is in a position right now where they are over-reading the tea leaves, where every small decision is followed by the question of what that decision indicates. A lot of those are questions that we won’t know very much about until the presidency has been up and running for a few years.

How have presidents handled appointing members of the opposing party into their Cabinets and senior staff?

Every recent president has tried to include at least one person from the opposite party in his Cabinet. Bill Clinton had William Cohen as his secretary of defense. George W. Bush had Norman Mineta as his secretary of transportation. Barack Obama had Ray LaHood, a congressman from Illinois, as his secretary of transportation. Often, the person appointed is a marginal member of the opposite party, and-or they get appointed to marginal positions in the administration. That is to say, if you had to make a list of the Cabinet positions, secretary of transportation is not exactly a really significant one. Secretary of defense is reasonably significant, but I think it’s fair to say that Cohen was known to be more liberal than most of the rest of the Republican Party. So, Trump may appoint one member of his Cabinet who is a Democrat, but it probably will not be to a particularly important position.