Former Democratic Sen. Tom Daschle, Obama's top supporter in South Dakota and leader of the effort to round up superdelegates, yesterday predicted the floodgates would open this week as remaining superdelegates jump on the Obama bandwagon.

"I think we're going to have a nominee before the end of this week," Daschle said on NBC's "Meet the Press."

The primary season ends tomorrow, with contests here and in Montana. Obama was spending yesterday, and all of Saturday, campaigning here.

Obama's complete break with Trinity United Church of Christ will provide a degree of cover for superdelegates poised to endorse him but possibly still uncomfortable about some of his entanglements.

And the same things that make it easier for Obama to cement his victory among superdelegates will help him coax independents to swing his way in the fall.

Obama hasn't yet declared that his nomination is inevitable. But he's on the very edge.

Clinton was winning roughly two-thirds of the votes in Puerto Rico yesterday, but even in defeat, Obama gained 17 delegates there, leaving him 47 short of the 2,118 needed to clinch the nomination.

"We are getting very close to the number, the new number, now that Michigan and Florida have been added," he told reporters traveling with him. "And if we've hit that number on Tuesday night we will announce that — and I think even if we don't, this is the end of the primary season," he said. Thus the in-your face decision to hold tomorrow night's primary season wrap-up rally at the Xcel Energy Center, site of the GOP convention beginning Sept. 1.

"I think it's very important for us to pivot and focus on the clear contrast that will exist between Democrats and Republicans in this election," Obama said.

Contributing to the dynamic as Obama heads toward the general election is that he has been painted so poorly by the Clinton campaign — from first portraying him as another manifestation of civil rights leader Jesse Jackson to suggesting her rival could be in the same line as other Democratic nominees who lost badly, including George McGovern, the 1972 candidate defeated by President Nixon in a landslide.

Clinton once worked for McGovern's candidacy. McGovern, also of South Dakota, earlier supported Clinton but switched his allegiance to Obama in May and urged her to drop out of the race. He described Obama's lead as "insurmountable" and argued "Democrats need to be gathering in a united way behind him."

Despite continued defiant assertions by Clinton that she would be a better candidate against McCain, even some of her most ardent supporters are now subdued, perhaps resigned to the inevitability of an Obama candidacy.

"He would make a good president, and we're not saying he can't get elected," top Clinton strategist Harold Ickes said yesterday.

Clearly, there are some big general election challenges ahead for Obama.

"Obama has to deal with the issue of white working-class reservations about him, highly social conservative attitudes," said Andrew Kohut, president of the independent Pew Research Center.

In many ways, Obama's resignation from the church and repudiation of ministers who made inflammatory comments from its pulpit should help with this group.

But more important, said Kohut, Obama needs to strongly reach out to independents. "Right now, they're breaking for Obama. All elections are about how independent voters break."

Plus, Obama is the first one to acknowledge that things happen, and that in a YouTube world, anything can rear up instantly — like the sermons of two preachers who are among his longtime acquaintances and supporters.

Remarks by his former pastor, the Rev. Jeremiah Wright, inflamed racial tensions. These were reinforced by recent comments from the same pulpit by a visiting pastor, the Rev. Michael Pfleger, that raised racial issues and mocked Clinton. Clips of both were circulated extensively on YouTube and television.

"I have to say this was one I didn't see coming. We knew there were going to be some things we didn't see coming. This was one," Obama said. "I didn't anticipate my fairly conventional Christian faith being subject to such challenge and such scrutiny, initially with e-mails suggesting I was a Muslim, later with the controversy that Trinity generated."

Tom Raum has covered Washington for The Associated Press since 1973, including five presidencies.