Let's see:
Abraham Lincoln (R) - assassinated.
James Garfield (R) - assassinated.
William McKinley (R) - assassinated.
John Kennedy (D) - assassinated.
Ronald Reagan (R) - assassination attempt.
So, President of which party is in greater jeopardy?
Or in other words, adherents of which party are more prone to violence?
Well if the Democratic party assassinated those folks you might have a point.
Collective guilt and punishment -- the hallmark thinking process of racists, morons, and other types of human monsters.