WASHINGTON - Sen. Barack Obama's aura of inevitability in the battle for the Democratic presidential nomination has diminished in the wake of his loss in the Pennsylvania primary and the furor over his former pastor, said the latest New York Times/CBS News Poll.

The poll was conducted largely before Obama's news conference Tuesday denouncing his former pastor, the Rev. Jeremiah Wright, and may not fully capture the impact of the controversy or the response. But it found that Obama, whose delegate lead has given him a commanding position over Sen. Hillary Rodham Clinton since February, is now perceived to be in a much tighter fight.

Upheaval has taken a toll

Fifty-one percent of Democratic primary voters say they expect Obama to win the nomination; 69 percent said so a month ago. Forty-eight percent of Democrats say Obama has with the best chance of beating Sen. John McCain, the presumptive GOP nominee, down from 56 percent a month ago.

Obama still holds an edge on several key measures: 46 percent say he remains their choice for the nomination, while 38 percent preferred Clinton, who has lost support among men. On that question, his margin grew, to 8 from 3 points, in the past month.

Obama also has an advantage over Clinton in ratings on honesty and integrity and in being less beholden to special interest groups.

But a month of political upheaval -- including a nearly 10-point loss to Clinton in Pennsylvania -- has taken a toll, and not just on Obama; 56 percent of Democrats described their party as divided. In contrast, 60 percent of Republicans see their party as unified, a striking turnaround from the Republican turmoil at the start of the primary season.

Adding to the volatility is the economy. Anxiety over that issue has continued to climb. More than four in 10 voters cited the economy as the one issue they want the candidates to address, up from about 30 percent in a CBS News poll in mid-March. (Only the war, cited by 17 percent, came close.)

The poll reflects the weakening economy in personal ways: As food and gas prices soar, more Americans say they are having a hard time saving or buying extras. Thirty-eight percent said they could do so in February, 27 percent now.

Eyes on November

Democrats see no early end to the Obama-Clinton battle, the poll found. About seven in 10 Democratic voters predict that their party's nominee will not be decided before the convention. And a plurality of voters say this will hurt their party's chances against McCain.

The survey suggests a very competitive race this November regardless of whom the Democrats nominate. In a head-to-head race between Obama and McCain, both candidates are backed by 45 percent of the registered voters. In a race between Clinton and McCain, 48 percent back Clinton, 43 percent McCain.

The nationwide telephone poll was conducted Friday through Tuesday with 1,065 adults, of whom 956 were registered to vote; it has a margin of sampling error of plus or minus 3 percentage points overall, and plus or minus 5 percentage points among Democrats primary voters alone.