For the more than fifty years that Democrats controlled the U.S. House of Representatives, leadership was divided between Massachusetts and Texas. When the Speaker was from Texas (or nearby Oklahoma), the Majority Leader was from the Boston area, and when the Speaker was from Boston, the Majority Leader was from Texas. 

The Austin-Boston Connection analyzes the importance of the friendships (especially mentor-protégé relationships) and enmities within congressional delegations, regional affinities, and the lynchpin practice of appointing the Democratic Whip.