Why Mike Johnson's perch has suddenly grown precarious

Politico.com - For more and to sign up click here To hear Mike Johnson tell it, he's not having much fun as speaker. He has complained about the long hours and constant travel, according to those who have recently spoken to him, and a series of escalating internal clashes have made the job a joyless slog. At least there's this: Many of his colleagues don't believe he'll be doing it much longer. Five months after…