Jeffrey Toobin has combined two great books in one. The first is an edge-of-your-seat thriller, describing Timothy McVeigh’s every movement on his way to committing one of the most horrific crimes in American history. The second traces how a huge part of the Republican establishment has come to embrace many of McVeigh’s most dangerous convictions. Toobin is a lawyer who became a full-time writer and TV pundit 30 years ago. This is his ninth book and his most important, because it gives the clear and present danger of rightwing extremism the attention it deserves. McVeigh was a brilliant marksman who...