SOLVED. Spy fiction soviet sleeper in US. [s]

[Lori]

Hi. Looking for a fiction spy novel about a man named Bill that is a secret service agent on the president's protection detail. He has a regular American home life. He gets a phone call and tries to assassinate the president but he doesn't know why. He begins to exhibit all kinds of odd behavior and finally realizes he is really a soviet sleeper spy. The song "Where have you gone Billy boy" is prominent in the book. Please help me remember the name of this book.

[Kris]

Lori, around what year did you read this novel?

[Lori]

In the mid 1990s

[Kym]

The Cain Conversion by Richard Aellen?

[Lori]

Omg. How did you find it!?!?!

[Lori]

Thank you!

[Kym]

You're welcome. I got lucky with WorldCat using keywords - Presidents, assassination, Year: 1980 - 1998, Non-Juvenile, Fiction, Book, English.

Came up on the second page :)