South Carolina Republican Sen. Lindsey Graham, one of the most hawkish US lawmakers, told Trump, "Mr. President, this is over the top," the book says.
He added that "with the election coming," Trump should temper his response and avoid risking "major war.".
Mick Mulvaney, Trump's chief of staff at the time, made an "urgent request" and "almost begged" Graham to "stop this talk of hitting Soleimani," the book says.
"The intelligence was very strong that Soleimani was orchestrating chaos in Iraq at our expense and throughout the region," Graham told "Fox & Friends" in January.
Trump and Graham were playing golf at the Trump International Golf Club in West Palm Beach, Florida, when Trump floated the idea.
"You've got to find a way to stop this talk of hitting Soleimani, Mulvaney almost begged," the book said.
Shortly after the strike, Iran essentially abandoned the 2015 nuclear deal, which Trump withdrew the US from in May 2018. »