The arrival of Palin on the national scene, with her youth, charisma and vitality, probably also portends a changing of the guard in Washington.

With Republicans having zero chance of capturing either House, and but a slim chance of avoiding losses in both, a Vice President Palin, with her reputation as a rebel and reformer, would surely inspire similar revolts in the Republican caucuses.

As Thomas Jefferson said, from time to time, a little rebellion in the political world is as necessary as storms in the physical.

The Palin nomination could backfire, but it is hard to see how. She has passed her first test, her introduction to the nation, with wit and grace. And the Obama-Biden ticket, having already alienated millions of women with the disrespecting of Hillary, is unlikely to start attacking another woman whose sole offense is that she had just been given the chance to break the glass ceiling at the national level.

Her nomination, which will bring the Republican right home, also frees up McCain to appeal to moderates and liberals, which has long been his stock in trade.

With his selection of Sarah Palin, John McCain has not only shaken up this election, he may have helped shape the future of the United States – and much for the better.