Base rates: There have been four presidential candidates assassinated in American history: Joseph Smith (Mormon Reform Party, 1844), Hale Johnson (Prohibition Party, 1902), Huey Long (Democrat, 1935), and RFK Sr (Democrat, 1968). The number of candidates, total... (making up numbers...) probably some several hundred.

Possible reasons to believe RFK Jr may be more likely than most to be assassinated:

• Higher level of political polarization, acceptability of political violence among certain groups.

• Positions viewed as extreme or dangerous by some portion of the population.

• Conspiracies theories:

  • If, as RFK Jr believes, the CIA has been responsible for the killings of previous Kennedys opposed to the CIA, RFK Jr could be similarly targeted.

  • If any conspiracy was responsible for the JFK assassination, RFK Jr's strong interest in releasing all relevant records could prompt some action to prevent the secret from becoming public.

• RFK Jr already had at least one possible assassination attempt.

Reasons he'd be less likely than most:

• RFK Jr has secret service protection. No presidential candidate with secret service protection has ever been assassinated (IIUC).

• RFK Jr is very unlikely to be elected president, as shown by his current low polling. As such, there is much less potential motivation for any would-be assassin.

• If RFK Jr were assassinated, there would likely be an immediate strong public interest in possible anti-Kennedy conspiracies. If any of the relevant conspiracy theories are true, those involved would have an interest in avoiding such close inspection.

Overall, I'd suggest the current price of 4% is an overestimate.