Giuliani’s potential criminal exposure is unclear. He was under investigation as recently as last summer by federal prosecutors in Manhattan for his business dealings in Ukraine and his role in ousting the American ambassador there, a plot that was at the heart of the impeachment of Trump. Giuliani did not respond to a message seeking comment. A spokeswoman for Trump did not comment either.
Such a broad pardon preempting any charge is highly unusual but does have precedent. In the most famous example, Gerald Ford pardoned Richard Nixon for all of his actions as president. Jimmy Carter pardoned thousands of American men who illegally avoided the draft for the Vietnam War.