Rand Paul and Hillary Clinton don't have a lot in common, and what they do have, both sides might like to downplay. But the wrangling ahead of Paul's formal declaration that he's running for president shows one interesting parallel between the two—the way they're handling their respective éminences grises, Bill Clinton and Ron Paul. Both men are being treated a little like crazy uncles in the attic—the type everyone knows about but doesn't acknowledge—and a little like wise gurus essential to victory.

In both cases, candidates seek to extend the reach of political dynasties. In both cases, the current candidates largely owe their prominence to earlier dynasts, and understand the fundamental political genius they bring to the table. But the current candidates (and perhaps more importantly, their advisers) also know that these founders like to talk and are liable to say something embarrassing and damaging, making managing them as essential as it is challenging.

In the case of Ron Paul, that meant that the retired U.S. representative and three-time presidential candidate was present at the Galt House Hotel for his son's big speech, but he didn't have a speaking part. That's likely to set the tone for the rest of the campaign, according to a report in The New York Times—Ron Paul isn't going to do much appearing in public.

But Rand Paul also can't completely disown him. Sure, he's his father, but he's also the fount of the political movement that has propelled the Kentucky senator into the race. Even as Rand Paul has built his own political identity and showed his own considerable political chops—he's probably a more talented politician than his father—he relies on the grassroots operation his father built over the course of many years. His need for the credibility his father offers with libertarians will only grow more acute as he edges toward the Republican mainstream to compete in the primary, adopts more hawkish stands on defense and foreign intervention, and risks alienating more dogmatic libertarians.

The refusal to compromise that made Ron Paul so beloved of that crew also often got him into trouble with the broader public. Paul pere says what he thinks, even when he seems to be thinking very little. He's recently embarrassed his son with off-the-reservation comments about Russia's invasion of Ukraine and the Ebola outbreak. Going further back, things get worse—like the racist newsletter published under Ron Paul's name.

The Times' account of how Rand Paul's team is handling Ron Paul recalls another story in the Gray Lady two weeks ago—about how Hillary Clinton's team is approaching the challenge of dealing with Bill Clinton. A few caveats are in order: Clinton is a more talented and successful politician than Ron Paul, one of the most talented of the post-war era. He also can't hold a candle to Paul's fringe beliefs, and he's never published racist newsletters. But that doesn't mean he's not just as challenging for his wife's campaign to handle.

Hillary Clinton has had a long and successful career in public service on the national stage, from the Senate to the State Department, but she doesn't have the natural volubility of many politicians, and it's tough to imagine her getting to the national stage without a boost from Bill Clinton's experience. He remains shockingly popular, especially among voters who remember the late '90s. He is also widely acknowledged as one of the sharpest political minds of his generation, with an ability to pore over maps and polling data and synthesize it like few others. Those are both assets any campaign would want.

How to marshal those skills without also pulling in his downsides, though? Bill Clinton proved to be a big liability in 2008—most notably when the man once hailed as "the first black president" incurred the wrath of black voters for criticizing Barack Obama and likening Obama's victory in the South Carolina primary to Jesse Jackson's wins there in the 1980s. Even his charisma and popularity can prove problematic, offering an unflattering contrast with the candidate herself. Last fall, when Hillary Clinton made her big return to Iowa, Bill won nearly as many headlines for his own speech and a gregarious gaggle with reporters.

There are signs that both men are learning to suppress their own political instincts, and defer to the new dynastic scions. Invited to make news about his wife's emails at the State Department, Bill Clinton demurred (though he couldn't help but point out that he was doing so). As for Ron Paul, he's been quiet in recent months and has been declining interview requests. Still, it's hard to imagine these veteran frontmen adapting smoothly to a role in the backing band. Either of them may be a good headache for the respective campaign, but there's no disputing that they are headaches.