In an email letter to supporters Sunday, Beto O’Rourke described the intense joy of being back with his family, “just hanging out, just being around just being — that I haven’t done in almost two years,” but how much he also misses the shared energy and higher purpose of the campaign just ended.

“Already miss the road. Miss our team and the volunteers we’d see in every city, every town. Miss the energy and joys and smiles that I found all over Texas. Miss the purpose, the goal. Miss being part of something so much bigger than me or my life. Organized for a common goal and end. We were all together, really together. Never felt anything like that,” O'Rourke wrote in the unusual missive.

U.S. Sen. Ted Cruz, R-Texas, defeated O'Rourke by 2.6 percentage points in his bid for re-election. O'Rourke had become a national Democratic star in the course of his campaign. The surprising closeness of the contest only heightened speculation about his future, most especially the possibility that he would seek the Democratic nomination for president to challenge President Donald Trump in 2020. O'Rourke said in answer to a question at the close of the campaign that he would not run for president in 2020, even if he didn't win the Senate race.

O'Rourke's third term in Congress representing El Paso ends in January.

The message to supporters, written in very personal terms, indicates that he feels an obligation to his young family and also to a campaign that for him and many of those he was addressing was more a cause and a movement.

"While there is loss, I also feel intense gratitude, waves of it everyday. How was I so lucky to be part of something so amazing?" he wrote. “We were doing this for one another, doing this the right way, doing this for our country at what we all know to be a defining moment of truth.”

O’Rourke acknowledged, “the loss is bitter, and I don’t know that I’ve been able to fully understand it.”

“I try not to ask what I could have done differently because I don’t know that there is an answer to those questions or thoughts,” he wrote. “There are a million different decisions I could have made, paths I could have taken, things I could have said or not said, said better or differently. I did my best, everyone did.”

But, at a moment when Trump and other Republicans are roiling the political waters questioning the legitimacy of continuing vote counts in a number of states, O'Rourke wrote, "For our democracy to work, for us to be able to continue to work together, it’s important to be at peace with the outcome.”

“But what remains is this: I’m the luckiest guy in the world to have had the chance to do this with you. To bring power and joy to politics. People instead of PACs. Communities instead of corporations. Polls and consultants left to the wind and hopefully to the past," he wrote.

O'Rourke said is not sure exactly how to assess what the campaign had wrought: “I don’t know how to fully make sense of what remains or to measure the impact we’ve had. Certainly we changed something in Texas and in our politics. At the very least our campaign reflected a change already underway in Texas that had not yet been seen in statewide campaigns."

“I am grateful that you gave me a chance to be part of this. I feel responsible to you, to our country, to my kids and to my conscience to make sure that we continue to find a way to respond to the urgency we still feel. It didn’t go away Tuesday night. Our ability to convert hope and inspiration into action and change must not be wasted or kept to a candidate to campaign lest it dissipate and be rendered unusable at the most challenging time in our nation’s history," O'Rourke wrote. "Just know that I want to be part of the best way forward for this country — whatever way I can help in whatever form that takes. Know that I am honored to have run this campaign with you and that I want to continue to honor and be honest to what was powerful about it."

"For the time being, I am going to focus on being a better dad to our kids who have not had much of one for the last 22 months,” O'Rourke wrote.

He closed, “See you down the road.”