One aspect of the film I havent seen much discussion about is WHO will be the intended victim of 1973 Mystique's assassination plot?
Senator Kelly (I dont know his age or if he was a Senator in this time in the film universe. Bruce Davison was 27 or so.)
Someone on imdb postulated Henry Kissinger.
The crowd at 1:28 and 1:40 in the trailer wave the flags of North Vietnam and South Vietnam and the police officers in the same scene wear French uniforms. Clearly we're at the Paris Peace Talks which led to the Paris Peace Accords between the US and the two Vietnams that ended the Vietnam War for the US. Also Magneto is aiming a gun at someone at 1:03 while standing in front of Eugène Delacroix painting "Liberty Leading the People" (although the painting is mirrored it is definitely "Liberty Leading the People") which hangs in the Louvre. The head of the US delegation at the peace talks was Henry Kissinger - so an educated guess would be that he is the person Mystique supposedly killed in 1973.