Joshua Matz didn’t bother waiting to write about the Supreme Court until he went to work there. He teamed with a renowned Harvard law professor to finish a book about the court before he started his year as a law clerk to Justice Anthony Kennedy. Unlike Matz, Christopher Michel is not listed as an author of the book he worked on years before his clerkship with Chief Justice John Roberts. But former President George W. Bush offered warm praise for onetime presidential speechwriter Michel as his collaborator on his memoir, "Decision Points." Bush said in the book’s acknowledgements that Michel’s...