The President's Daughter By B. Clinton and J. Patterson

VP  Matt Keating becomes president of the United States when the president unexpectedly dies. During a SEAL mission (ordered by Matt) to kill a ruthless terrorist, the terrorist survives but his whole family is killed accidentally. He vows revenge on Matt--no matter how long it takes. Fast forward a few years, and Matt is no longer president. His very ambitious VP, Pamela Barnes, decided to run against him and won. So he and his daughter Mel are living in New Hampshire and his wife is back teaching anthropology and working on digs in a nearby state, with regular visits to NH. Though Matt and his wife still have Secret Service protection, his college-age daughter no longer does. Dave Stahl, one of Matt's agents, keeps trying to loosely keep Mel protected till his boss orders him to stop. And shortly afterward, Mel is kidnapped by the ruthless terrorist.  Matt vows to get his daughter back using his own SEAL skills from back in the day, Dave's help and some connections he made when he was president. It's quite the page-turner as Matt struggles to find out if Mel is still alive and where she could be, the ruthless terrorist keeps making threats, and a Chinese intelligence agent thrown in the middle of all this is ordered to get the terrorist to turn the girl over to him, to improve Chinese-American relations but of course has his own secret agenda.

I loved Matt's wife, Samantha, who hated living in DC and is the one who has the real measure of the new administration and how much (or really how little) they are going to help her and Matt get their daughter back. Good beach book or book for a long flight.