Well folks, here we are in the final stretch of the one of the most unpredictable and unconventional presidential campaigns in American history. And Republican presidential nominee Sen. John McCain (Ariz.) and his running mate, Alaska Gov. Sarah Palin, against the ropes and hoping for a knockout blow, are throwing punches below the belt.

[IMGCAP(1)]The news that McCain and his campaign will go even more on the offensive should not alarm Democrats. There’s good news: Sen. Barack Obama’s (D-Ill.) presidential campaign has learned an important lesson from Sen. John Kerry’s (D-Mass.) failed 2004 campaign: Hit back, hard.

Over the weekend, Palin earned her “Sarah Barracuda” nickname. This pit bull in lipstick may not know what the Bush doctrine is, but she will darn well learn what the Obama doctrine is before she resumes her duties as Alaska’s governor on Nov. 5: Hit back, hard.

Obama isn’t waiting until tonight’s debate to respond to a new round of attacks. Pre-emptive strike, here comes the Obama doctrine.

Let’s start with Palin’s untruthful accusation of Obama “palling around with terrorists.” Charges of guilt by association with ’60s radical Bill Ayers have already been proved baseless by every reporter in America — on the air, in print and online. Obama has been vetted. We’ve been there, done that and even seen Republican candidates lose primary contests in ruby-red districts by slinging the same kind of baseless guilt-by-association charges.

Nevertheless, a desperate McCain campaign is hoping character assassination will pull the voters’ attention away from their disappearing money market funds, retirement accounts and job security. They are dead wrong.

As one astute political strategist told me over the weekend, “There is no need, then, for the Obama campaign to answer to these scurrilous charges with specifics.” The strategist is betting that the public will take the charges as seriously as the Obama campaign makes it.

The tone of the response is what’s important. It should be as dismissive as it is immediate. The Obama campaign needs to note that these charges were asked and answered during the primary. It’s October, and the McCain camp is conjuring up Halloween tales that might scare children but not adults.

Voters aren’t interested in recycled mud. They’re too busy worrying whether they will have a house to live in next month. What’s important now are the issues facing our nation: the economy, rising health care premiums, our decline in manufacturing, the sudden stoppage of cash flow to small businesses and the responsible return of our troops from Iraq.

Of course, McCain wants to change the subject, especially when it comes to the economy. The possible economic collapse is the first, second and third most important issue in this election — and McCain is running from it like a scalded dog.

There’s an old GOP debating trick that the McCain camp has been employing in these closing days of the campaign. If you watch closely, you’ll see McCain use it tonight in the debate: throw out a bunch of lies and make your opponent use his time defending himself rather than making his case for himself and against you.

The strategy put in place this summer when McCain revamped his campaign was to keep Obama on the defensive. And they did a great job hammering away at Obama by unleashing attack ads, videos and attack-dog surrogates to insinuate that Obama is “unacceptable,” “risky” and “unworthy” of being commander in chief. And now comes Palin with her below-the-belt questioning of Obama’s patriotism.

Democrats must react to these attacks but not by tossing back more mud. Obama should use the remaining days of the campaign to repeatedly present the unified theme of change. Turning the page on hyperpartisanship so the country can get things done has been the benchmark of his historic campaign.

Voters want a fundamental course correction for America’s ship of state. They want a change from the failed policies and governance of President Bush and GOP-elected officials. Obama still has time to present his vision of change in a compelling and authentic way. His campaign style and tactics must reflect what he offers most to the electorate — a new generation of leadership for a new century.

Go back to the issues, Sen. Obama, and allow others to watch your back. Stay the course. Tell voters how you will reform our economy, revitalize our exhausted armed forces, rebuild our crumbling infrastructure and reclaim our shared core values.

The only change McCain offers is himself. He has become a cynic who will abandon any belief and say anything to get elected. McCain’s entire campaign is now based contemptuously around the theory that people respond only when their worst and most selfish desires are ignited. The McCain campaign embraces what Roosevelt called a “sneering disbelief in the selflessness of others.”

At her first and last debate on the national stage, Palin faulted Sen. Joseph Biden (D-Del.) for mentioning the Bush administration failures. Yet she and McCain show every intention to make the same set of mistakes with the same air of arrogance and insularity. She won’t face the media and answer questions about her tenure in office and where she stands on important issues. Is that too much to ask someone who is applying to be one heartbeat away from the presidency of the United States?

Or am I being sexist by raising the question?

Donna Brazile, the campaign manager for Democratic presidential nominee Al Gore in 2000, runs her own grass-roots political consulting firm.