<Tr> <Td> </Td> <Td> Robert Bork (not confirmed) </Td> <Td> 7001300000000000000 ♠ 30 </Td> </Tr> <Tr> <Td> </Td> <Td> Anthony Kennedy </Td> <Td> 7001110000000000000 ♠ 11 </Td> </Tr> <Tr> <Td> </Td> <Td> David H. Souter </Td> <Td> 7001200000000000000 ♠ 20 </Td> </Tr> <Tr> <Td> 1991 </Td> <Td> Clarence Thomas </Td> <Td> 7001250000000000000 ♠ 25 </Td> </Tr>

Who appoints u.s. supreme court justices and how long do they serve