In The Washington Post, Mark Feldstein tells how the 1960 Kennedy campaign did opposition research on RN’s links to Howard Hughes.
How did JFK’s campaign obtain this incriminating evidence? By paying the contemporary equivalent of $100,000 to a Los Angeles accountant named Phillip Reiner, one of the Hughes middlemen used to conceal Nixon’s role in the deal. Reiner was a Democrat who recently had had a falling-out with his partners. With his attorney, Reiner had contacted Robert Kennedy, his brother’s campaign manager. Soon after, a break-in occurred at the accountant’s old office – and the Kennedys suddenly acquired a thick file filled with secret records documenting Nixon’s shady deal. (Reiner’s estranged partner filed a burglary report with the police, but the crime was never solved.)
With hard evidence in hand, the Kennedy camp passed the dirt to [columnist Jack] Anderson.