Nixon was removed by the Watergate frame up. The two attempts on Reagan—assassination and Iran-Contra–missed. After Russiagate and impeachment failed, Trump was taken out with a stolen election covered up with the "Trump Insurrection."
President Carter could also have been a victim of the military-security complex. He was talked into the risky rescue of US embassy personnel held hostage by the Iranian revolution. The military managed to completely botch the rescue, and used the presstitutes to blame Carter.
Kennedy, Nixon, Carter, Reagan were the peace-minded presidents who worked for better relations with Russia (the Soviet Union as it was known at the time). Clinton, George W. Bush, and Obama are the presidents who did the most to raise tensions with Russia. The military/security complex did not act against these three presidents.