Editor's note: David Frum, a CNN contributor, was a special assistant to President George W. Bush from 2001 to 2002. He is the author of six books, including "Comeback: Conservatism That Can Win Again," and is the editor of FrumForum.
Washington (CNN) -- There's a lot to like about Herman Cain. He's funny and personable. He's a great American success story. His 9-9-9 tax plan may be half-baked, but the concept behind the plan -- replace the corporate income tax with in effect a consumption tax -- has a lot to recommend it. (Although, the plan has a lot of problems, too.) Finally, in a political cycle that has seen too many coded racial attacks on President Obama and his family, it's a source of great pride to me to see an African-American topping my party's polls.
If Herman Cain had served as governor of Georgia, or even mayor of Atlanta, he'd be a valid and credible candidate for president of the United States.
But here's the trouble: he has not held those offices or any other executive office at any level of government. He did serve on the board of the Federal Reserve Bank of Kansas City in the 1990s, including two years as chairman -- a distinguished position and an important responsibility, but not one that involves the management of a public agency.
So everything! The president's most fundamental job is to run the government. That job is very, very hard. The consequences of a mistake are very, very serious.
For that reason, Americans have historically demanded a record of successful accomplishment in public office from their presidential candidates. The current president is an exception to the rule, and -- well -- enough said.
Barack Obama became president despite a negligible record in large part as a reaction against the perceived failures of the George W. Bush presidency. Many voters in 2008 made a calculation like: "Obama may never have governed anything. But George W. Bush was a two-term governor of the country's second biggest state, and he got us into Iraq and a terrible recession. So maybe experience doesn't count. Maybe what we need is a different style: somebody more cautious than Bush, somebody who doesn't always go with his gut."
You might expect Republicans to react similarly against the Obama presidency, demanding from their nominee skills that Obama lacked: administrative experience, negotiating skill, deep policy knowledge.
But no. From Donald Trump to Michele Bachmann to Herman Cain, the Republican activist base has again and again fixed its hopes on people who have never held an executive public office -- and who defiantly reject the very idea of expertise.
Meanwhile Mitt Romney -- the man who saved the 2002 Olympics and who inaugurated the nation's first universal health insurance program as governor of Massachusetts -- can't rise above 25% or so among Republicans. And the seemingly most logical alternative to Romney -- Texas Gov. Rick Perry -- has collapsed in the polls. Perry may not be the sharpest pencil in the pack, but he can at least claim experience in government.
The Trump, Bachmann and now Cain boomlets reveal a worrying disinclination among some Republicans not to value government management very highly. These voters assume that if a candidate professes the right values, he or she will make the right decisions.
Barry Goldwater gave this disregard its classic expression in his "Conscience of a Conservative."
"I have little interest in streamlining government or in making it more efficient, for I mean to reduce its size. I do not undertake to promote welfare, for I propose to extend freedom. My aim is not to pass laws, but to repeal them."
But guess what? Repealing laws is just as hard as passing laws. A president who wishes to extend freedom must still staff his or her administration with people who can do their jobs. And the more you reduce government's size, the more important that what remains should work well.
Back in 2008, National Review editor Rich Lowry talked about a Republican "competence primary." That year, the Republican field was dominated by candidates who could claim some huge success in government: Romney; New York's crime-fighting former Mayor Rudy Giuliani; and the very effective three-term governor of Arkansas, Mike Huckabee. The race was won by John McCain, the man who had devised and pushed the "surge" strategy that turned around the Iraq war.
This time, apparently, the competence primary has been canceled. Too bad. In the depths of the worst economic crisis since the Depression, competence is needed more than ever.
The opinions expressed in this commentary are solely those of David Frum.