This is a cropped, close-up of U.S. President Obama shaking the prosthetic hand of Medal-of-Honor recipient U.S. Army Sargent 1st Class Leroy Petry. Sargent Petry's prosthetic hand is almost vertically oriented. His ability to position the angle of his hand is obviously significantly limited. Despite this, President Obama still orients his hand in a more dominant, 45 degree, palm-down position. An alpha personality, particularly a president or head-of-state is very accustomed to being "The most important Alpha in the Room". Here is one occasion where he should acquiesce.
Do you know how Nonverbally counter the dominant palm-down handshake?