White House policy advisor Stephen Miller on Monday described the late Sen. Lindsey Graham, R-S.C., as a personal friend and the most effective advocate for President Trump's agenda in the Senate. Miller's remarks, made during a White House tribute, revealed a closer relationship between the two than had been publicly known.

"Lindsey was of a mold that I don’t think we’re going to see for a very long time," Miller said. "He was someone who really understood how the power of rhetoric, how the power of communication as a senator can actually change outcomes." Miller added that Graham "really believed you could change people’s minds through the force and persuasion of his rhetoric."

Miller characterized Graham as a key ally whose support was instrumental to the administration. "Lindsey was the most effective, consistent advocate for the president’s agenda in the Senate," Miller stated. "That is a historical legacy that will always belong to him."

Graham, who died suddenly at age 71, was described by Miller as being "fundamentally good to us, to all of us." Miller expressed gratitude for Graham's willingness to assist the administration, noting, "Every time we needed everything and anything at all, we called Lindsay. Without question, without hesitation, he would help out." Miller emphasized the importance of recognizing Graham's generosity of spirit and the reasons many people were drawn to him.

Graham's death was attributed to an aortic dissection due to arteriosclerotic cardiovascular disease, according to a preliminary cause of death released by his office. An aortic dissection occurs when a tear forms in the inner wall of the aorta, the body's main artery, creating a life-threatening medical emergency.

Following Graham's death, South Carolina Gov. Henry McMaster, with President Trump's approval, appointed Graham's sister, Darline Graham Nordone, to fill his Senate seat. It remains uncertain whether Nordone will seek a full six-year term in the upcoming special election.

Potential Republican candidates for the seat are rumored to include Reps. Nancy Mace and Ralph Norman, both of South Carolina. According to state law, the Republican Party must hold a primary election on August 11 to select its nominee.