SAN ANTONIO, Texas --Barack Obama is hoping that Tuesday night at a big outdoor rally in chilly San Antonio, he and several thousand supporters can celebrate victories in Texas and Ohio. And if it happens, it could be enough to finish off Hillary Clinton once and for all and virtually clinch the democratid nomination for Obama. But Clinton is fighting back with everything she has to keep that from happening, and on Monday at least, she is getting some help from a big corruption trial back in Chicago. The Democratic heavyweights are winding up the most combative and intense week in Texas. But front-runner Obama is trying to clean up a mess back in Chicago by admitting it was, "boneheaded" to buy a house next to indicted businessman Tony Rezko at a time when he was under investigation. But Obama says all of Rezko's campaign cash has been donated to charity and that's the end of it. "I have been very open about what I called a bone-headed move. On the other hand, there have been no allegations that I did anything wrong," Obama said. But Obama's decision to end the news conference before all the questions were answered is prompting an uncharacteristic blow back from the media. Meanwhile, Clinton is continuing to aggressively bombard Obama for lacking experience, failing to do anything substantive with his Afghanistan subcommittee in the Senate and talking negatively about the NAFTA trade treaty while his emissaries allegedly tell Canada is just politics. "I don't have my campaign tell a foreign government behind closed doors,' that's just politics. Don't pay any attention.' I tell you what I mean. I think we have to renegotiate," said Clinton. "We have put out a statement. It wasn't true. I don't know who the source is," Obama said. Clinton realizes that unless she wins in Ohio and Texas or finishes very close in one, that her campaign may in fact be over. The latest polling shows a dead heat in Texas, with Clinton maintaining a small lead in Ohio. In Vermont and Rhode Island, those are such small states that the outcome is worst mentioning but not relevant as to whether she stays in the race. The Obama campaign is so concerned about the Rezko trial they sent someone in to watch in federal court to make sure there were no surprises. It is only jury selection. Senator John McCain was in Texas Monday night. He could clinch the Republican nomination with big wins Tuesday. He is just 225 delegates shy of sealing the deal. Earlier in Phoenix, the former Navy pilot and POW talked about his years of foreign policy experience. "I have been involved in every major national security challenge in the last 20 years that has faced this country," said McCain. Republican Mike Huckabee spoke at a rally in Houston. The Dallas Morning News endorsed the former Arkansas governor Monday.