Lindsey Graham's sudden death has shocked the political world ... not least of all because he was one of the most active members of the Senate -- something we experienced firsthand recently.

Remember ... our TMZ DC team caught up with the senator from South Carolina less than a month ago, and our cameraman Charlie chatted with him about Freedom 250 -- the UFC fight on the White House Lawn.

Of course, Senator Graham was a busy man ... and Charlie got him while on the move -- following along while the senator tackled several flights of stairs like they were NBD, chatting all the while.

Graham was an avid golfer as well, regularly hitting the links with President Donald Trump ... including multiple times in one week back in 2017.

In the weeks before his death, Graham won the senatorial primary in South Carolina ... and made multiple campaign stops in the state prior to his win -- a schedule which can be quite taxing on a politician.

Graham was also active in the Senate in recent weeks ... even introducing a bill on June 23 to mark July 15 as "Glioblastoma Awareness Day."

As you know ... Senator Graham passed away Saturday night after what his team described as a "a brief and sudden illness."

TMZ DC obtained photos of Graham being wheeled out of his home on a gurney ... and 911 audio indicates he apparently had chest pains prior to his death.

President Trump and other world leaders -- like former President Joe Biden and Ukraine President Volodymyr Zelenskyy -- paid tribute to him in the aftermath of his passing.

Graham served in the Senate from 2003 to 2026 after spending 8 years in the U.S. House of Representatives.

He was 71.