In 1948 Harry Truman criss-crossed the country by train in what looked like a hopeless campaign for reelection as President. Polls showed that he didn't have a chance. His "whistlestops" were drawing small, lukewarm crowds.

One morning, his train pulled into the farming community of Dexter, Iowa. Instead of a small, listless group, an enthusiastic crowd greeted the President. Among those on the platform was a lawyer named Carroll Switzer. Truman had never met Switzer before, and after this brief meeting he moved on with his campaign.

The polls turned out to be wrong, and Truman won the election. A few months later, a vacancy occurred on an Iowa District Court. The President brushed aside names suggested to him. The assistant to an Iowa Senator recalled what happened:

"Every time the Iowa judgeship came up, Truman would hear of no one but Switzer. Truman would say, "That Switzer backed me when everyone else was running away, and by God, I'm going to see that he gets a judgeship."

The President Appoints  If You're Lucky!

Carroll Switzer got the chance to wear the black robes of a federal judge because he happened to meet and impress a president. Luck can play an even larger part in winning one of the rare Supreme Court seats.

A few months after her appointment to the Supreme Court, the first woman Supreme Court justice, Sandra Day O'Connor, commented:

"While there are many supposed criteria for the selection of a justice, [the nomination] is probably a classic example of being the right person in the right spot at the right time. Stated simply, you must be lucky."

Justice O'Connor did have the right legal background, such as experience on an Arizona state court. But her luck included the fact that great pressure had built up to name a woman to the highest court. In addition:

• She was the right age (51). Most Supreme Court nominees are in their 40's or early 50's. Presidents want their choices to serve on the court for many years. So they rarely choose older people.

• She was a judicial conservative, the kind of judge Reagan wanted. Only a person who favored judicial restraint had any hope of being named by President Reagan. Judicial restraint is a judge's willingness to accept the laws of Congress and of state legislatures whenever possible.

• A good friend and law school classmate already sat on the Supreme Court. Justice William Rehnquist spoke up for her nomination.

On the Bench for Life?

To protect the independence of the judicial branch, judges of the District Courts, Courts of Appeals, and the Supreme Court keep their jobs during "good behavior." The phrase is in Article III of the Constitution. In effect, they serve until they die or choose to retire. They cannot be forced to retire even if they become disabled. (Judges of lesser federal courts, such as customs courts, serve specific terms.)

Federal judges can be removed only by the rare and difficult process of impeachment. Only 11 federal judges have ever been impeached, and only five of those were actually removed.

The Constitution gives federal judges another protection. Their compensation, or pay, "shall not be diminished during their continuance in office."

The judiciary has been called the weakest of the three branches. Yet lifetime appointments give federal judges great independence. Judges may serve 30 or more years, handing down rulings on laws of the land.

Who can Become a Federal Judge?

The Constitution sets no rules at all. In practice, however, a person needs a law degree. Other qualifications have become customary over the years.

• Legal competence. The Justice Department checks the legal qualifications and ability of those the President might appoint. For instance, suppose a state court judge is being considered for a Circuit Court of Appeals. The background check shows that half of the judge's decisions have been reversed by higher courts. The judge probably would not get a recommendation.

  The American Bar Association, the attorneys'"union," also checks out the nominee. A 14-member Committee on Federal Judiciary talks to people who have worked with candidates, and studies their legal experience.

  The President may ignore these findings. Nominations do not necessarily go to someone ranked "exceptionally well-qualified" or "well-qualified."

• Political party. Presidents are not in the business of rewarding people in the opposing party. Federal judgeships are an important part of the patronage a President can hand out. Only about 6 percent of those named to District or Circuit Courts have not belonged to the President's party. Surprisingly, about 15 percent of Supreme Court choices belonged to the other party.

• Residence and geographical balance. Federal District Court judges must live in the district they serve. There is no residency rule for Circuit Courts. Yet by custom, at least one appeals judge is picked from each state in the Circuit.

  To satisfy people from all parts of the country, Presidents try to see that all regions are represented on the Supreme Court. Lincoln, for instance, had a vacancy to fill, and insisted that it go to someone from west of the Mississippi River.

• Religion, race, and sex. When a vacancy occurred on the Supreme Court in 1932, other justices, legal scholars, and Senators urged President Herbert Hoover to choose Benjamin Cardozo of New York. But there was a problem. Cardozo was Jewish, and the so-called "Jewish seat" on the court was already filled. Over the years a tradition had developed that one seat on the Supreme Court went to a Roman Catholic and one to a Jewish justice. When justices holding those seats died or retired, Presidents usually named someone of the same religion.

  This tradition did not allow for two Jewish justices. Nor did it allow for women, blacks, or other minorities. But the informal rules can be changed. Cardozo did get the nomination and, much later, so did a black and a woman justice.

The Senate Confirms . . . Sometimes!

After a person is nominated to the federal bench, the Senate must confirm, or reject, the nomination. Before the Senate takes its vote, however, the Senate Judiciary Committee screens the nominee.

For District Court judges, the committee traditionally consults the Senators from the state where the vacancy occurs. Carroll Switzer would not have become a district judge if an Iowa Senator had objected. Only if the state's Senators approve does the nomination go forward. (This custom does not hold for the higher courts.)

If committee members have doubts about a candidate, they may delay the start of hearings. By stalling, they give those who oppose the candidate time to organize. Robert Bork, one of the most controversial candidates for the Supreme Court, was nominated on July 1, 1987. The Judiciary Committee did not begin its hearings until mid-September. Not surprisingly, it voted against nomination, and so did the Senate.

Adapted from The Presidency, Congress, and the Supreme Court, Scholastic Inc., 1989.