Guess if you want to be president and make significant changes, the best defense against the heart attack gun is to have a relationship with some intelligence agency, or some faction within an intelligence agency, that has serious dirt on powerful people who are against you. That way they can set up a dead mans switch and release info if you die of a heart attack. But then those agents you have a relationship with may want to have dirt on you as well in exchange for their help, if they don't already. They might ask you to do something that could be used against you.