"I fully believe at the end of the day there's going to be Republican support for this bill," he said.
The Congress will get a health care bill to the president's desk by the end of this year because, Baucus said in a press conference, it has a moral obligation to do so, giving the issue "a certain sense of inevitability."
"This is our moment in history," he said. "We cannot let this opportunity pass."
Baucus said his bill meets all of President Obama's criteria for health care reform; he said it provides security and stability for those with insurance, expands coverage to those who do not, slows the growth of health care costs, and "keeps insurance companies honest" by providing competition. It also stays within the president's preferred price range of $900 billion over 10 years, reduces the deficit over 10 years and controls long term spending, he said.
"We have done everything imaginable to get the most generous, most affordable coverage that we could within President Obama's target," Baucus said.
The senator's bill has been attacked from the left for not doing enough to make health care coverage accessible and affordable. Baucus acknowledged the complaints from both sides of the aisle and said a "bipartisan" approach is more durable and better policy.
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"I believe I have an obligation to work as diligently and as hard as I can to try to get the most broad-based bill possible," he said.
He said, however, he is not yet sure how many Americans would be covered under his bill. He said it is most likely in the mid to low 90's.
"I don't have exact estimate, but... we don't want coverage to get too low," he said. "If coverage gets too low, then we start to -- to no longer have the benefits of virtually universal coverage."
Baucus defended his provision to tax insurance companies for the more expensive plans they offer, even though some have criticized the tax will be passed down to consumers.
"I think it's appropriate to get the fat out of insurance companies," he said.
The tax would prompt insurance companies and employers to provide fewer benefits, he said, and to compensate for lost benefits with increased income -- taxable income.
Negotiations to win some Republican support for the bill are continuing with "talking, working with, exploring, probing, cajoling," Baucus said.
"It's just -- being creative about it."
CBSNews.com Special Report: Health Care