The president choice of federal judges is based on their policy inclinations. liberal presidents tend to appoint or choose judges that are liberal inclined while conservative presidents tend to prefer conservative judges.
The president of the United States designates magistrates who neither conservatively or liberally interpret the United States' Constitution exactly as it is written instead interpret it in his own view. This is the main reason why the Supreme Court does not have only a single judge and have a group of judges. the reason behind this is that different views are required and everyone interprets uniquely.
