So are two other attributes. One is character. Richard Nixon was qualified by his experience as congressman, senator and vice president, but disqualified by character. The second is a braided mental rope of constitutional sense and political common sense.

In his Denver speech, Barack Obama derided the "discredited Republican philosophy" that he caricatured in four words -- "you're on your own." Then he promised to "keep ... our toys safe." Among the four candidates for national office, perhaps only Palin might give a Madisonian answer -- one cognizant of the idea that the federal government's powers are limited because they are enumerated -- if asked to identify any provision of the Constitution, other than the First Amendment, that imposes meaningful limits on congressional or executive authority to act.

If so, she would be a good influence on Washington, including McCain. But is there any evidence that she has thought about such matters? McCain's selection of her is applied McCainism -- a visceral judgment by one who is confidently righteous. But the viscera are not the seat of wisdom.

In 1912, McCain's Arizona became the 48th state. In 1959, Palin's Alaska became the 49th. Western conservatism has the libertarian cast of a region still steeped in an individualism natural to the frontier's spaciousness. But American conservatism depends on what it calls "fusion," the collaboration of libertarians and social conservatives concerned that liberty unleavened by restraints creates a licentious culture. Palin supposedly is fusion in one person.

Many cultural conservatives, who are much of the GOP's base, consider McCain's adherence to their persuasion perfunctory. By his selection of Palin, he got the enthusiasm of the base. But what has he got in Palin? In coming days he and we will learn from a stern teacher, experience.