State of Terror by Hilary Clinton and Louise Penny

 This is quite the page-turner, though you have to pay attention because there are a lot of moving parts. 

When Douglas Williams is elected president, he makes a surprising choice for Sec of State--Ellen Adams, a woman whose media company had roundly lambasted him for months. He's thinking he'll get her away from her media company, keep her out of the country, and publicly humiliate her as much as possible. But he doesn't know Ellen Adams.

When terrorists blow up buses in three European cities, Ellen is determined to find out who is behind it, what their next move is--and to identify the high-level traitor in the White House. And at her side is her long-time best friend, Betsy (who truthfully was my favorite character in the book).

Be sure to read the notes at the end for a touching explanation of where the names for some of the main characters came from.