When the president of the United States speaks, the world listens, so long as the mic is on. Since 1968 that mic has been the Shure SM57 in a dual configuration. Dual mics add redundancy, and frankly, a sense of importantance.
One SM57 is usually wired to house audio, and the other to a breakout box which is fed to media outlets. In all the years I've been watching Presidents talk (since Carter!) I've never heard a dropout or tech failure--a salute to the rock solid reliability Shure SM57s have.