Red, White, and Blood by Christopher Farnsworth

"This is not a man. In almost a hundred years, I have seen it shot, stabbed, drowned, burned, decapitated, dismembered, and buried. And in almost a hundred years, there's only one thing that's ever been able to kill it.Me."

The campaign trail, 2012: A political operative of the incumbent president and a party volunteer are brutally murdered while in a compromising position. A message has been written in their blood.
"IT'S GOOD TO BE BACK"
A centuries-old horror has returned to taunt Nathaniel Cade, the President's Vampire. Under constant threat of exposure-and with enemies old and new at every turn-he and his handler Zach must stop the one monster Cade has never been able to completely destroy. And they must do it before the creature known as the Boogeyman adds another victim to his long and bloody list: the President of the United States.