Let’s be candid with each other: I have never heard (and I bet you haven’t, either) anyone explain that in the upcoming presidential primary he intends to vote for Johnny Geesil, rather than any of the other seven active presidential candidates, because his home-state lieutenant governor had publicly endorsed Geesil. We don’t deliver milk or bread in this country, and nobody — not even popular lieutenant governors — delivers votes.

A respected neighbor or friend who is especially civic-minded and knows more about the candidates’ records and character can often influence our vote in a lower-information political contest. I was never exactly sure just what a county recorder did (although, as my old Cleveland friend Tim Hagan once pointed out, the spouse of a county recorder could qualify as “the first lady of recording”), so a trusted colleague who vouched for the trustworthiness of recorder candidate Jones might well deliver my vote.

But not for president. This is personal. We might not be sure what it takes to make an outstanding county coroner. But all of us have definite ideas of just what qualities we value in a would-be president.

Not only that, but in presidential contests, each of us is the beneficiary (or, maybe, the victim) of information overload. We know that Newt Gingrich has been married three times and that Mitt Romney, Ron Paul, Rick Santorum, Michele Bachmann, Jon Huntsman and Rick Perry have each been married once.

We have learned that Perry and Paul both served honorably in the military, while Romney, Gingrich, Santorum, Bachmann and Huntsman — like President Barack Obama and Vice President Joe Biden — instead chose not to wear their country’s uniform. Although Gingrich — apparently seeking some form of innocence by association — regularly offers as a credential that his father did serve in the Army for 27 years. (Sorry, Newt, nobody gets credit for a relative’s service.)

The Washington Post reported that “Gingrich hopes to roll out endorsements from members of Congress, in part to counter the assertion that he alienated many of his colleagues as House speaker in the 1990s.” While endorsements do not seem to matter much to presidential voters, they seemingly do matter to presidential candidates.

According to Roll Call, the Capitol Hill newspaper, Romney, who has never served in Washington, has public endorsements from 55 Republican members of Congress from 30 states. Gingrich, who has been in politics for 33 years and who, as speaker in 1995, was Time magazine’s Man of the Year, has been endorsed by just eight congressional Republicans — only three of whom come from outside of Georgia, the state Gingrich represented for 20 years.

Like every good rule, there is an exception to the one about endorsements not mattering in presidential contests. If the individual giving the endorsement is, in fact, a brother, sister, child or spouse of the endorsee’s opponent on the ballot, it deserves our attention. In 2008, former New York City Mayor Rudy Giuliani was the father of two voting-age children — a son who was not speaking to the candidate and a daughter who was volunteering for Obama. His campaign was never able to explain this nonsupport. So, too, it would rate coverage if Mrs. Gingrich were on Monday morning to endorse Huntsman.

So the general rule does apply: If you want heading into the Iowa caucuses and the New Hampshire primary to be the political sage of the water cooler, pay minimal attention to presidential candidate endorsements, because — other than the candidate being endorsed and the politician endorsing — that’s exactly what voters do.

Mark Shields is one of the most widely recognized political commentators in the United States. The former Washington Post editorial columnist appears regularly on CNN, on public television and on radio. Click here to contact him.