The big fights -- war and peace, justice and liberty -- are important. But there aren't any small fights. And where Paul made the biggest impact -- where his work resulted in the greatest improvement of people's lives -- was on issues that don't usually lead anyone's stump speech: mental health, domestic violence, homelessness among veterans.

Paul's brother, Stephen, had struggled with mental illness since he was 19. And Paul knew that many people who suffered from mental health problems were forced to suffer all over again because their insurance companies wouldn't cover the treatments they needed. Paul's own parents spent 20 years paying down the bill for Stephen's treatment.

So he found a Republican with a similar first-hand understanding of the problem, New Mexico Senator Pete Domenici, and the two introduced legislation that would require insurance companies to treat mental health the same way they did physical health. Paul didn't live to see mental health parity become law -- but it did (thanks in large part to another Republican colleague, Minnesota's Jim Ramstad), and that crusade has improved, even saved, millions of lives.

Paul's wife Sheila -- really, she was his partner, in everything he did -- wasn't a natural politician. She was pretty shy. But she traveled the state, visiting with survivors of domestic abuse, and was similarly inspired to take action. When the Violence Against Women Act passed, Joe Biden said that Sheila might have done more to achieve the victory than any senator. Like Paul, she saw an opportunity to improve people's lives, and did the hard work to make it happen.

When your guiding principle is to focus on improving people's lives, politics is a lot easier to navigate. Right after Paul took office, he held a press conference in front of the Vietnam Veterans' Memorial to protest the Gulf War. Veterans groups were furious -- and Paul realized they were right to be. He made sure to meet with as many veterans as he could -- not just to apologize, but because he realized he had a lot to learn from them. That's how he came to be one of the nation's leading advocates for veterans' health care -- and how veterans became an important part of his base. The political problem solved itself, because Paul didn't treat it as a political problem, but rather as an opportunity to help people.

Reaching out to those who might not seem like natural allies, fighting passionately on any issue where there was a chance to improve people's lives, being compassionate enough to see suffering where others have overlooked it and human enough to admit a mistake -- these things were all part of what made Paul successful. But there was one more thing.

As Paul once said: "If we consign ourselves merely to the poetic, utopian discussion of what should be and neglect the prosaic, practical work of the electoral politics that is, we doom ourselves to the margins of political life." In other words: You gotta work.