Jeff Jacoby
It's the oldest political rap against Mitt Romney: He is an ideological weathervane, a politician with a well-deserved reputation for conveniently changing past positions. His history of ideological reinvention – from a self-described moderate whose "views are progressive" to a "severely conservative" Republican – has been explored, attacked, defended, and ridiculed ever since he began testing the presidential waters eight years ago. Like his business acumen, his storybook marriage, and his Mormonism, Romney's political switchbacks have become a mainstay of his public image.

The former Massachusetts governor will give one of the biggest speeches of his political career at the Republican convention here tomorrow night. An essential goal of the speech is to reboot that public image. Party conventions are no longer just about rallying the faithful. More important is making a good impression on the "persuadables," the narrow slice of the electorate that is still undecided about whom to vote for, or at least open to a convincing argument to change their minds.

Romney's nationally televised acceptance speech may be his best chance before November to assure ambivalent voters that his core beliefs are not apt to shift with the prevailing breezes. With Hurricane Isaac's capricious winds and unpredictable trajectory, there has been no shortage here of meteorological metaphors for expressing the virtue of political dependability.

But a counter-theme pulsing through this GOP convention week is that there are times when people should reverse themselves on significant political issues. If you were convinced in 2008 that putting Barack Obama in the White House was of surpassing importance, Republicans in Tampa want you to know: It's OK to change your mind.

But a counter-theme pulsing through this GOP convention week is that there are times when people should reverse themselves on significant political issues. If you were convinced in 2008 that putting Barack Obama in the White House was of surpassing importance, Republicans in Tampa want you to know: It's OK to change your mind.

Jeff Jacoby

Jeff Jacoby is an Op-Ed writer for the Boston Globe, a radio political commentator, and a contributing columnist for Townhall.com.