A new Gallup poll shows that Gore's selection of Sen. Joe Lieberman virtually erased George W. Bush's lead overnight. How could that be?

Here is the sound political calculation Al Gore and his staff made for why Lieberman was a shrewd (as well as a wise) choice:

1. Increases Interest in the Convention
The historic nature of Lieberman's candidacy guarantees maximum media interest in the Democratic campaign just in time to limit the GOP's post-convention "bounce" and shift public attention from Philadelphia to Los Angeles. It might also increase the number of people who watch the convention on TV, which itself could be a major achievement.

2. Reinforces Gore's Centrist Message
Like Bill Clinton's equally daring choice of Gore in 1992, Gore's choice of Lieberman reinforces the critical impression that he leads a New Democratic Party. Lieberman will solidify the message that the Gore administration will represent not a throwback to an earlier era of liberalism but a continuation of the Clinton policy legacy, determined to modernize government, exercise fiscal discipline, embrace and shape the New Economy, and reflect the economic interests and cultural values of the American mainstream.

3. Appeals to Independents
Gore has two political problems at the moment. He has been trailing George W. Bush among the 30% of the electorate made up of independents, and he is failing to attract the kind of monolithic support from Democrats that Bush is gaining from Republicans. The Lieberman choice shows that Gore realizes the first problem is more critical and harder to reverse than the second. In Connecticut, Lieberman has shown remarkable political strength among independents, and even among Republicans, winning re-election by a landslide in the Republican landslide year of 1994, and he is currently running about 50 points ahead of his Republican challenger in the 2000 race (an "LBJ law" in Connecticut will allow Lieberman to continue his Senate re-election campaign while running for vice president).

4. Provides Gravitas With Humor
Republicans will find it impossible to characterize Joe Lieberman as a partisan attack dog. He more than matches his rival, Dick Cheney, in the gravitas department. A senior member of the Armed Services Committee, Lieberman has quietly emerged as the successor to former Sen. Sam Nunn as the most thoughtful Senate Democrat on defense issues. His and Gore's support of the Gulf War resolution will preempt any suggestion of unwillingness to use force. And unlike Cheney, Lieberman has a long and distinguished resume on domestic issues, especially education, technology, the environment, and efforts to curb the marketing of sex-and-violence-laden entertainment products to children. Furthermore, for all his reputation as a serious moral thinker and statesman, Joe Lieberman is universally regarded as one of the wittiest politicians in America--actually winning a recent competition in Washington for stand-up comedy.

Lieberman's strength is probably best illustrated by the fact that initial Republican response to his selection was to claim he is closer to George W. Bush than to Al Gore on several key issues. Lieberman will quickly disabuse the public of that notion, but it shows he is the rare politician that cannot be frontally attacked, even in the heat of a presidential campaign. Placing him on the ticket was a bold, shrewd move by Al Gore that bodes well for autumn.