Zeke J. Miller at Swampland transcribes Barbara Bush's comments on why Jeb Bush shouldn't run for president:

I think this is a great American country, great country, and if we can’t find more than two or three families to run for high office, that’s silly, because there are great governors and great eligible people to run. And I think that the Kennedys, Clintons, Bushes, there are just more families than that. And I’m not arrogant enough to think that we alone are raising, but we’re — we’re raising public servants, whether they’re feeding the poor, like Lauren is, who’s fed 68 million children around the world, or Barbara, who’s bringing global health to the world, or Pierce is working for Big Brothers, Big Sisters.

But there are a lot of ways to serve. And being president is not the only one.

Here's video:

The important sentence in the above quote is the one where she name-checks the Clintons. If Jeb Bush doesn't run for president and Hillary Clinton does run for president, the Republican Party will make a big show out of that statement. Though it's hard to believe the party of George W. Bush making a political issue out of presidential dynasties, that's absolutely something that could happen.