Liz Cheney has ended her Senate candidacy in Wyoming, citing family health concerns. She had been trailing far behind incumbent Republican Sen. Mike Enzi in polls. Analysts have speculated on why she was running so weakly: She had only been living in the state briefly after years in Virginia; affection for the Cheney family had worn off over the years; Republican primary voters are no longer attracted by the assertive foreign policy championed by Cheney and her father, the former vice president; voters were turned off by her opposition to same-sex marriage and her disagreement on that issue with her sister Mary.

I think all that is beside the point, and that Cheney's candidacy was doomed from the beginning. The reason: Wyoming is a small state; despite its large land area, it has fewer people than any other state (or the District of Columbia). And in small states -- like Wyoming, Montana, the Dakotas and Delaware -- Senate races are essentially personal.

Senators and Senate candidates are expected to get around the state, and voters expect to talk, person to person, with their senators multiple times during their six-year terms. They develop personal relationships. Candidates with obnoxious personalities don't get elected in such states. Senators who stop getting around the state frequently don't get re-elected. Those who do seldom lose, even if they are partially incapacitated by illness, like Tim Johnson of South Dakota. After he was stricken and partly paralyzed at age 59, he was re-elected by a wide margin in 2008; people knew him, felt sorry for him, admired his determined efforts at recovery -- and getting around to see them again.

Cheney's candidacy was doomed once three-term Sen. Enzi announced his run for re-election. Enzi gets around the state, holding frequent ice cream socials, waiting for everyone else to speak at town hall meetings until he chimes in. He is also a hardworking senator who masters serious public policy issues (note his trenchant criticism of Obamacare before it was passed). Wyoming voters admire him but, more importantly, consider him an old and trusted friend. They were not going to vote him out, even for a challenger who was arguably a bit more conservative, even for a challenger who came from a well-known and still widely admired Wyoming family.

Note that when Dick Cheney was elected to the House of Representatives in 1978, he was not running against a Republican incumbent. It was an open-seat race: Four-term Democratic incumbent Teno Roncalio was not running for reelection. Dick Cheney had been Gerald Ford's White House chief of staff, but he did not campaign on his laurels. Rather, he returned to the state and campaigned person-to-person, even as he was recovering from one of his early heart attacks.

Had Mike Enzi not run for re-election, Liz Cheney might have won similarly. But she was not going to beat a popular incumbent.

I think Liz Cheney might have had a better chance of being elected to the Senate if she had run in Virginia, where she lived for many years, either in 2012 for the open seat won by Democrat Tim Kaine or next year against incumbent Democrat Mark Warner. Cheney has a good command of important issues and has worked as a serious high-level assistant to her father, and would have been a plausible and high-profile candidate against either of these two popular Democrats. Virginia is our national bellwether state these days, voting closest to the national average in the 2008 and 2012 presidential elections; both Republicans and Democrats can win statewide.

But of course that means that a Virginia Senate seat can't ever be regarded as safe. Mark Warner, despite high popularity, may have a serious challenge if former Virginia Republican Party and Republican National Committee chairman Ed Gillespie runs (the Weekly Standard's Bill Kristol is boldly predicting Gillespie would win). In contrast, for a Republican who stays in touch with voters, a Wyoming Senate seat is, for all practical purposes, safe, as Mike Enzi has just shown.

Perhaps that's one reason Cheney decided to run in Wyoming and not in Virginia.