Paul told an incredulous Leno he and his son haven't discussed whether the Kentucky senator will run in 2016, and he said his son's Senate campaign was itself a surprise. Paul said he didn't expect his son to do well in that race, but he did thanks to grassroots tea party support.
But the proud father didn't seem to have doubts now. Leno asked him who he thinks will get the Republican nomination in 2016.
"Probably somebody who lives in Texas - I mean used to live in Texas, lives in Kentucky now. He'll probably end up getting it," Paul said.
Leno also asked if Rand Paul is moving in a moderate direction, especially with comments he made recently praising some of President Barack Obama's decisions.
"If I call him a moderate, I'll destroy his political career," Ron Paul said, but he also noted that he, too, agrees with the president in some cases, including his recent openness to possibly engaging Iran in direct talks.