Ask any boxing trainer and he'll tell you that you can walk into the ring with a well-designed plan to beat your opponent, but as the fight progresses, you might have to alter your plan.

After losing 11 straight races to Sen. Barack Obama, Sen. Hillary Clinton was faced with a tough choice: continue on the same path and keep losing or shake up your fight plan to keep battling another day.

She accepted the "resignation" of her campaign manager, Patti Solis Doyle; brought in Maggie Williams; paid more attention to her campaign finances, especially online fundraising; and went after Obama with a different line of attack, which some have described as negative.

Frankly, the "3 a.m." ad that questioned his qualifications as commander in chief — without overtly saying it — should be seen only as negative, based on the tone and tenor of this campaign. But it will pale in comparison to the ads we will see in the fall. That, folks, is just smart politics.

So she won three out of four states, staved off defeat, and now has a little pep in her step heading into the Wyoming caucus, Mississippi primary and the big contest on April 22, the Pennsylvania primary. More importantly, she has forced Obama to question his campaign plan and put the onus on him to go to his corner to get instructions from his trainer in order to win the next round.

Obama faces a tougher task because of his denunciation of the politics of old, which has sort of tied his hands. He is expected to be Mr. Positive on the campaign trail and not go negative against Clinton. Yet there are ways in which he can define Clinton better that not only will not be seen as negative but also will reposition him better leading into the final contests.

For one, the Clinton campaign successfully has sold the media on the idea that the next important contest is Pennsylvania. The day after her wins Tuesday, nearly every show was talking about what needs to happen April 22, as if the Wyoming and Mississippi races were afterthoughts.

Obama must hit Clinton hard on being a "big D" Democrat who doesn't really care about the "little d" democrats. Remember how she essentially brushed aside Obama's wins in Utah, Idaho, Washington state and other places as nothing but red states they have no way of capturing in the fall? Her argument is that Democrats must win the big states: California, New York, Ohio, etc. This plays to her advantage because she won them. (Sorry, I don't include Michigan and Florida, and you already know why.) This falls in line with her "50-plus-1" strategy: Just win the same states as Al Gore in 2000 and John Kerry in 2004, and then you flip Ohio or Florida to win the White House.

But Obama's thinking is more in line with Democratic National Committee Chairman Howard Dean: Create a 50-state strategy to establish Democratic dominance on the federal level — more of a supermajority — but also on the state level.

By changing the discourse and suggesting that she will only care about Dems in large states, he will be able to speak to the hearts and minds of those small states, and more importantly, he will rally those superdelegates who felt put off by Clinton's dismissive comments.

A key argument for Obama to make is that redistricting is two years away, and Democrats need control of governorships and state legislatures. Only through targeting those places will that become a reality.

Second, jump right in her face on the foreign policy front. She claims she was integrally involved in the release of Kosovo refugees and the Irish peace talks. Fine. So demand the following: If you were so involved in foreign policy, why did the Clinton administration fail in Rwanda and have a horrible plan for Somalia? There were clear international failures during the eight years of President Bill Clinton, and she needs to be forced to say what she did and didn't do. Obama has used the cherry-picking argument but has been weak in selling it. Nail it to try to nail her.

Finally, professor Obama has to return. One of the reasons he did so well in the Los Angeles debate is that he chose to go head-to-head with her on policy. Everyone said that's her strength, but he held his own. He needs to make a more convincing argument when it comes to the economy. The economic plans they have are not overwhelmingly different. What he has to do is come out from behind the podium and make it plain. Speak to voters in Mississippi about the tragedy of the Gulf Coast; tell voters there and in Wyoming why he will help their kids go to college; present his urban and rural economic renewal programs to the voters in Pennsylvania. Don't concede any ground to her on these points.

Is this fight over? Absolutely not. But Obama can't afford to look at his lead among pledged delegates and think he will maintain that and go to Denver with the superdelegates' support. In Las Vegas, every boxer is told to win it in the ring and not depend on the judges.

This is now a 15-round heavyweight match instead of 12 rounds. Clinton has no choice but to brawl. It worked Tuesday, so why stop doing it?

Obama? He is sort of the boxer who is technically proficient and wants to showcase those skills. But you can't dance all night. Sometimes you've got to slug it out in the middle of the ring. That doesn't mean being nasty or trashing your opponent. But it does mean fighting hard until the bell rings in the final round and never letting your guard down.

Obama, you let your guard down before Tuesday. Don't do it again, or you just might get knocked out of the nomination.

Roland S. Martin is an award-winning CNN contributor and the author of "Listening to the Spirit Within: 50 Perspectives on Faith." Please visit his Web site at www.RolandSMartin.com. To find out more about Roland S. Martin and read his past columns, visit the Creators Syndicate Web page at www.creators.com.

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