I can’t verify this quote, but besides Sen. Tom Cotton, Lindsey Graham appears to be the other senator:
[Facebook, 1/11/20] “Trump has reportedly now confessed that he ordered the assassination of General Soleimani in exchange for the votes of war-mongering Senators Graham and Cotton in his impeachment trial.” Nicholas Davies
Trump reportedly told associates he killed Qassem Soleimani because he was under pressure from GOP senators before his impeachment trial
President Donald Trump told associates that he assassinated Iran’s top military leader last week in part to appease Republican senators who’ll play a crucial role in his Senate impeachment trial, The Wall Street Journal reported on Thursday.
In a lengthy piece detailing how the president’s top advisers coalesced behind the strike on Iranian Maj. Gen. Qassem Soleimani, The Journal reported that Trump had told associates he felt pressured to satisfy senators who were pushing for stronger US action against Soleimani and who will run defense for him on impeachment.
One of Trump’s most outspoken supporters, GOP Sen. Lindsey Graham, appears to be the only congressional lawmaker Trump briefed about his plan to assassinate Soleimani in the days leading up to the strike.