One of the most troubling aspects of a Donald Trump presidency is the stamp he might place on the federal courts.

Congress can pass a law, and the president can sign it, but if a federal court rules that the law violates the Constitution, it won’t survive. It’s no secret that Americans United’s core issues – religion in public schools, taxpayer aid to sectarian institutions, the meaning of religious freedom, access to birth control, government’s use of religious symbols and language, etc. – usually end up in court. The courts are often our last line of defense on church-state issues.

To understand why the power to appoint judges is so important—and not just at the Supreme Court level, it’s necessary to look at the structure of our federal court system. Federal trial courts – formally known as U.S. District Courts – exist in all 50 states, Washington, D.C., and U.S. territories. District courts are the first rung of the federal judiciary. There are 94 of them. A populous state like California has four district courts, while Alaska has just one. Cases start with these courts.

The next level is the federal appellate courts. They are divided into 13 circuits, most of which are geographic and include several states. Appellate panels consist of three judges.

Above them sits the Supreme Court of the United States.

In movies and televisions shows about lawyers, you might hear someone vow to take a case all the way to the Supreme Court. It makes for dramatic TV, but in reality, it’s not likely to happen. The Supreme Court accepts less than 2 percent of the cases it is asked to hear. And it is asked to hear only a tiny portion of the suits that are filed and litigated. Most lawsuits, therefore, are resolved by a lower court. And that means the judges on the federal appellate and trial courts are often the last word not just in resolving disputes but also in making and interpreting the laws that govern all of us.

So how do judges get on those courts? When a sitting federal judge retires or dies, the president gets to name a replacement. According to the Constitution, the Senate is expected to offer “advice and consent.” This means that the Senate votes on the president’s judicial nominees. With a simple majority of 51 votes, the candidate is confirmed. (The House of Representatives plays no role in this process.) 

Trump could change the nature of federal courts during his presidency. 

Can presidents change the composition of the federal courts? Definitely, if there are enough vacancies.

Here’s an example: Prior to Barack Obama’s presidency, we at Americans United were wary of bringing cases in the U.S. 4th Circuit Court of Appeals, which includes the states of Maryland, West Virginia, Virginia, North Carolina and South Carolina. The circuit had a reputation for being very conservative and hostile to our issues. If at all possible, we avoided litigating there.

But a number of judges on the circuit retired or stepped down, and Obama replaced them with moderates. These days, the atmosphere for church-state cases in the 4th Circuit is much improved.

Trump could, unfortunately, take things in the opposite direction.

We have a vacancy on the Supreme Court right now, and that’s getting a lot of attention – as it should. But we need to remember the importance of the lower federal courts. Too often, nominees to those courts don’t capture national headlines and thus don’t receive the scrutiny they should.

Trump has talked generally about the kind of judges he’d like to appoint, and he has even issued a few names of potential Supreme Court nominees. AU’s Legal and Legislative Departments are researching these men and women, learning all we can about their views on church-state issues.

But we won’t stop there. We’ll examine all of Trump’s judicial nominees at all the court levels. If a nominee presents cause for concern, you’d better believe that we’ll sound the alarm.