On Jan-6, Trump proved he controlled citizen militias (who continue to support him from prison).
Romney pays $5,000. a month of his own money for protection. As Romney admitted, most congressmen and senators cannot afford to pay for their own protection. Since the government does not provide politicians with protection and their home addresses are public knowledge, they are sitting ducks.
As we saw with Brett Kavanaugh and other Supreme Court judges, American judges are also terrified of Trump's power over citizen militias.
Like it or not, Trump has built a private army that answers to him and only him. No law enforcement agency in this country has the authority, or funding necessary to protect everyone targeted by Trump's militias.