If I had planned to speak for 13 hours when I took the Senate floor Wednesday, I would’ve worn more comfortable shoes. I started my filibuster with the words, “I rise today to begin to filibuster John Brennan’s nomination for the CIA. I will speak until I can no longer speak” — and I meant it.

I wanted to sound an alarm bell from coast to coast. I wanted everybody to know that our Constitution is precious and that no American should be killed by a drone without first being charged with a crime. As Americans, we have fought long and hard for the Bill of Rights. The idea that no person shall be held without due process, and that no person shall be held for a capital offense without being indicted, is a founding American principle and a basic right.

My official starting time was 11:47 a.m. on Wednesday, March 6, 2013.

I had a large binder of materials to help me get through my points, but although I sometimes read an op-ed or prepared remarks in between my thoughts, most of my filibuster was off the top of my head and straight from my heart. From 1 to 2 p.m., I barely looked at my notes. I wanted to make sure that I touched every point and fully explained why I was demanding more information from the White House.

Just before 3 p.m., Sens. Mike Lee (R-Utah) and Ted Cruz (R-Tex.) came to the Senate floor to help out. Under Senate rules, I could not yield the floor or my filibuster would end, and Majority Leader Harry Reid (D-Nev.) could have shut me down. The only way for me to continue and allow Sens. Lee and Cruz to speak was to yield the floor for questions.

Their presence gave me strength and inspiration. Sen. Jerry Moran (R-Kan.) also arrived to help. Sen. Ron Wyden (Ore.), the only Democrat who came to my defense, explained how we have worked together to demand more information from the White House about the rules for drone strikes. At about 4:30 p.m., Sen. Marco Rubio (R-Fla.) joined. I was flagging for a while, but these senators kept me going.

Sen. Reid came to the Senate floor to ask me when I would be done so he could schedule a vote. But I wasn’t ready to yield. I felt I had a lot more explaining to do.

At about 6:30 p.m., something extraordinary happened. Sen. Mark Kirk (R-Ill.), who has been recovering from a stroke, came to the floor to give me something. I was not allowed to drink anything but water or eat anything but the candy left in our Senate desks. But he brought me an apple and a thermos full of tea — the same sustenance Jimmy Stewart brought to the Senate floor in the movie “Mr. Smith Goes to Washington.” That was a moment I will never forget.

Sen. Cruz came to the floor again just before 7:30 p.m. and said, “Given that the Senate rules do not allow for the use of cellular phones on the floor of the Senate, I feel quite confident that the senator from Kentucky is not aware of the Twitter-verse that has been exploding.”

I had little idea of what was going on. I was allowed only to talk and listen to questions. As I started to walk around the Senate chamber to loosen up my legs, I was energized by the responses on Twitter. Sen. Cruz really lifted my spirits when he read the tweets.