For the past two years, Sen. Rand Paul (R-Ky.) has openly been laying the groundwork for a run for president. It often seems like his mind is already made up about running.

"Just coincidence, probably just coincidence, yeah," he recently quipped to a local reporter about the release date of his forthcoming book, which is it set to hit bookstores next year.

But Paul's wife Kelley sounds much less thrilled with the idea.

"I mean it's something that you don't go into lightly, being in the public eye is hard on a family and a marriage," she recently told WKU public radio in Kentucky. "I'm really proud of Rand, I think he's doing an amazing job, so I'd love for him to be able to expand that but we still have a few hurdles to cross before we actually pull the trigger on it."

In late 2013, Paul suggested his wife was leaning against it.

"There's two votes in my family," he said at the time. "My wife has both of them. Both of them are 'no' votes right now."

There are a couple of ways to look at what Kelley Paul is saying these days. One is to read her comments as a real sign that Paul may not be as sure a bet to run for president as most people think. A presidential campaign is demanding enough in its own right; to not have your spouse 100 percent on board is a big reason not to run. (Just ask Mitch Daniels.)

Another is to read it like this: What Paul's wife is apparently doing -- a deep and careful consideration of the potential negatives of running for president -- is a process other politicians' spouses have gone through before giving their blessings.

Take first lady Michelle Obama, who was not always full steam ahead publicly on the idea of her husband running for president.

"No comment," Michelle Obama told CNN in November of 2006, when asked if she was ready to be first lady.

The reality is that we often just don't know until an announcement is made.

There's no doubt that Paul really wants to run for president. Everything he does -- from sweeping policy speeches to building a national political network to visiting Iowa and New Hampshire -- says he's in.

But Paul's wife's comments are a reminder that decisions about presidential campaigns are often far more personal than professional.