It is fitting, I suppose, that at the same time Sen. Rand Paul (R-Ky.) lets on that he wants to go back to medicine at some point, he scores another four Pinocchios for his false assertion that we had no planes to rescue our people in Benghazi, Libya.

Sen. Rand Paul, R-Ky., speaks at the Conservative Political Action Committee annual conference in National Harbor, Md., Friday, March 7, 2014. Friday marks the second day of the annual Conservative Political Action Conference, which brings together prospective presidential candidates, conservative opinion leaders and tea party activists from coast to coast. (AP Photo/Susan Walsh) Sen. Rand Paul (R-Ky.) speaks at the Conservative Political Action Committee annual conference in National Harbor, Md., on March 7.  (Susan Walsh/Associated Press)

You certainly can understand the attraction of medicine for Paul. As a doctor, he is competent, doing good, receiving praise and in command of his facts when treating patients. But in politics, he remains a lightning rod, frequently dinged for odd conspiratorial theories or, quite frequently, for getting facts wrong. He bristles at criticism and, not unlike President Obama, accuses critics (even on the right) of bad faith.

The irony is that Paul need not exaggerate or misstate facts to make some of his points. Without falsely asserting there was “no plane” to rescue our people in Libya, he certainly could have made the point that we were caught unaware or that we foolishly ignored signs of al-Qaeda’s influx into Libya or that the Ben Rhodes memo suggests an instantaneous obsession with politics over accuracy and good policy. In the case of the Iraq war, Paul, as liberals did, could have reiterated the CIA’s failure to determine there were no longer WMDs in Iraq or criticized the rosy expectations; instead he went around the bend, insinuating that the vice president dragged us into a war for pecuniary gains. In the case of the National Security Agency, he simply could make the argument (although I disagree with it) that the data mining was excessive and prone to abuse; instead, he repeatedly and falsely asserts that the NSA is listening to your phone calls.

It is one thing to utter such things to get applause at the University of California at Berkeley, but presidential candidates — even senators — are held to a higher standard. One can speculate that Paul does what he does because he wants to stand out or that he is prone to fantastical theories, as was his father. Or one can surmise that he really doesn’t have a good grasp of details and hasn’t assembled a staff to keep him out of trouble. But it really doesn’t matter what the reason is. You wouldn’t hire an eye doctor who continually exaggerated and got his facts wrong. Nor would Paul have gotten to be a successful eye doctor had he been prone to such habits in his practice. And so it is that mainstream Republicans, evangelical Christians, business people and big donors remain stubbornly resistant to his candidacy.

Now, many politicians exaggerate and get their facts wrong. But the frequency with which Paul does so, and the absence of some quality control in his office is, I would suggest, rather unique in the U.S. Senate. And if his supporters and staff complain that he is criticized more than his peers and subject to disproportionate scrutiny, they surely must know that an all-but-declared presidential candidate routinely gets this. One’s overt ambition invites it. An actual candidate gets even more scrutiny every day.

In selecting the presidential nominee, Republicans are talking about the person the party will trust to keep the White House from Hillary Clinton and who, if elected, will be charged with matters of life and death and the most difficult domestic policy calls. For that august responsibility, many Republicans will want someone as sober, detail-oriented and accurate as Dr. Paul, not Sen. Paul. And that remains his overriding problem should he, as we fully expect, run for president.