I submit the following as mandatory requirements for any Supreme Court justice:
1. Absolute integrity.
2. Commitment to the constitution and constitutional law.
3. Ability to subordinate personal belief and preference to the constitution and the law.
4. Intellectual ability to weigh issues and to decide wisely based on evidence, fact, and logic.
5. Sound knowledge of the law and the constitution.
Integrity is the first and most important characteristic. A justice must not be subject to bribery, blackmail, undue influence or anything that could interfere with good decisions. Intelligence and ability without integrity are dangerous; an intelligent but unethical justice can use his ability to hide misdeeds and to persuade other justices to support tainted decisions.
Second, justices must be committed to our constitutional form of government, and to constitutional law. We have a representative republic with carefully crafted protections against abuse of power and the court must uphold that form of government. Substitution of its own wisdom for the constitutional law of the land would put the court the position of a dictator. Legislation should be left to senators and representatives who are accountable to the voters; the court is not a super-legislature.
Third, justices must subordinate their own beliefs and desires to law and constitution. One mark of a good judge is to set aside personal preference and judge according to the law. To do otherwise would again be putting himself in the position of dictator, imposing his own will on the electorate. We need justices who can say, "I dislike this law. I think it is dumb. However it is the law and it is constitutional so I must let it stand." Justices must recognize that they are "hired hands," employed to serve the people according to the "contract" set forth in the constitution. They may think that a law is stupid, and in this they may be right. However they must recognize that voters and their representatives have a right to make laws, even stupid laws.
Forth, justices must have the intellectual wherewithal to deal with the issues they will face. This seems obvious. Not only are the issues themselves often complex, but there are smart lawyers arguing each side. A justice must be able to consider all aspects of a case, cut through the intellectual fog, and decide on the basis of fact, logic, law and constitution.
Fifth, and again rather obviously, judicial nominees must have a sound knowledge of the law and the constitution. They must know and understand the basis on which they are to decide.
The president must reject the temptation to appoint justices who will advance a political agenda, instead seeking those who meet the above requirements. Justices should be judges, not politicians.