This is where Paul really stepped up.
Noting the location -- the Ronald Reagan Presidential Library in Simi Valley, California -- Paul said with regard to the "wouldn't talk to him" line: "Well, think if Reagan had said that during the Cold War? We continued to talk with the Russians throughout the Cold War which [was a] much more significant [challenge than] where we are now."
"Should we continue to talk with Iran? Yes. Should we cut up the [Iran nuclear] agreement immediately? That's absurd. Wouldn't you want to know if they complied? Now, I'm going to vote against the agreement because I don't think there's significant leverage, but it doesn't mean that I would immediately not look at the agreement, and cut it up without looking to see if whether or not Iran has complied.
"The same goes with China. I don't think we need to be rash, I don't think we need to be reckless, and I think we need to leave lines of communication open. Often we talk about whether we should be engaged in the world, or disengaged in the world, and I think this is an example of some who want to isolate us, actually, and not be engaged.
"We do need to be engaged with Russia. It doesn't mean we give them a free pass, or China a free pass, but, to be engaged, to continue to talk. We did throughout the Cold War, and it would be a big mistake not to do it here."
There was a similar moment when the question of intervention in Syria arose.
The Kentuckian said:
"I think this gets to the point of wisdom on when to intervene and when we shouldn't. Had we bombed Assad at the time, like President Obama wanted, and like Hillary Clinton wanted and many Republicans wanted, I think ISIS would be in Damascus today. I think ISIS would be in charge of Syria had we bombed Assad.
"Sometimes both sides of the civil war are evil, and sometimes intervention sometimes makes us less safe. This is real the debate we have to have in the Middle East.
"Every time we have toppled a secular dictator, we have gotten chaos, the rise of radical Islam, and we're more at risk. So, I think we need to think before we act, and know most interventions, if not a lot of them in the Middle East, have actually backfired on us."
There are plenty of issues on which Rand Paul is wrong. He is not so steadily anti-war as his father, former congressman and 2012 presidential contender Ron Paul, or as "old-right" Republicans like North Carolina Congressman Walter Jones Jr.
There are plenty of things that Paul has said and done that merit skepticism, and opposition.
But the senator -- and his dissenting views with regard to foreign policy -- belonged on the main stage Wednesday night. Indeed, it was Rand Paul, not Donald Trump, who made Wednesday night's gathering of Republican presidential contenders a debate.