But Paul's case -- and Kentucky as a state -- is different.
Firstly, it's important to note that Democrats held on to the state House this year, which means Paul can't count on his first, best option: the state legislature changing the law to allow him to run for both reelection and for president (not every state prohibits this, but Kentucky does).
As a fallback, the state GOP could look at changing their presidential primary into a caucus. Paul could also sue to overturn the law preventing him from being on the ballot twice. Another option broached by Shane Goldmacher is defeating Secretary of State Alison Lundergan Grimes (D) in 2015 and installing a new Republican secretary of state who might be kinder to Paul's cause.
But Paul doesn't technically need any of that.
That's because the 2016 Kentucky Senate primary is May 17 -- at least three months after the first presidential primary contests. And given Kentucky is a pretty red state that Democrats might or might not target at the Senate level, Paul has more room to maneuver than Portman or Rubio.
In addition, Kentucky is one of those states that holds governor's races in odd years, and 2015 just happens to be one of those odd years. That means relatively few people will be focusing on the 2016 Senate race until late 2015. The 2010 Senate race that Paul won, for instance, didn't really begin until August 2009, and that was because there was an open GOP primary. It seems unlikely Paul would face real opposition in the primary, so he can wait even longer this time.
Paul could simply run for president for the next year-plus, and if he's not a/the front-runner come January 2016 (or earlier), simply revert to his Senate campaign.
Here are the important dates in that process (with the very tentative presidential dates based on the yeoman's work of Josh Putnam at the Frontloading HQ blog):
- Jan. 18, 2016 -- Iowa caucuses
- Jan. 26, 2016 -- New Hampshire primary
- Jan. 26, 2016, 4 p.m. -- Kentucky candidate filing deadline
- Feb. 2, 2016 -- Colorado caucuses, Minnesota caucuses, New York primary, Utah primary
- Feb. 6, 2016 -- Nevada caucuses
- Feb. 13, 2016 -- South Carolina primary
- Feb. 16, 2016 -- North Carolina primary
- Feb. 23, 2016 -- Michigan primary
Again, most of these are tentative dates, based on Putnam's deductions, but it's a fact that this process tends to move toward early January the longer time goes on. That would mean that Paul could be able to run in a few states before he would even have to make a final decision. And very few campaigns tend to last beyond these early contests, so at that point, he would know if he was in the lead pack.
For Democrats, the name of the game here is to put pressure on Paul -- make him sweat. That's going to be pretty tough, though, given Grimes just got swamped in the 2014 Senate race. Who is going to step forward to run for Senate in mid-2015 who isn't more interested in running for governor in 2015?
If Paul had more to be worried about in his reelection bid -- like Rubio and Portman -- this might not work out so well. For now, though, it's quite conceivable that he can run for both until late January.
Would he prefer not to have to pull the trigger on Jan. 26? Of course. But we're guessing, by that point, we'll know whether Rand Paul for President is likely to win the nomination or not. He's a high-upside candidate who is likely either going to do very well or flame out early, and there's probably not much in-between.