Washington ? In the first poll since John Kerry locked up the Democratic nomination, Kerry and President Bush are tied while independent Ralph Nader has captured enough support to affect the outcome, validating Democrats’ fears.

The Republican incumbent had the backing of 46 percent, Kerry 45 percent and Nader, the 2000 Green Party candidate who entered the race last month, was at 6 percent in the survey conducted for The Associated Press by Ipsos-Public Affairs.

Bush and the four-term Massachusetts senator, who emerged as the nominee Tuesday after a string of primary race wins over several rivals, have been running close or Kerry has been ahead in most recent polls that did not include Nader.

Since Nader entered the race Feb. 22, campaign strategists and political analysts have been trying to assess the impact of another presidential bid by the consumer advocate whom some Democrats blame for Al Gore’s loss in 2000.

Four years ago, Nader appeared on the ballot in 43 states and Washington, D.C., garnering only 2.7 percent of the vote. But in Florida and New Hampshire, Bush won such narrow victories that had Gore received the bulk of Nader’s votes in those states, he would have won the general election.

Exit polls from 2000 show that about half of Nader’s voters would have backed Gore in a two-way race. Nader dismisses the spoiler label.

While Nader’s support in the AP-Ipsos poll was 6 percent, his backing in polls in 2000 fluctuated in the single digits — often at 4 percent, but sometimes higher. This year, Nader is unlikely to get the Green Party nod and faces a stiff challenge in getting his name on the ballot in 50 states.

Kenneth Freeman, an 86-year-old retiree from New Smyrna Beach, Fla., who leans Democratic, was clearly unhappy with Nader’s presidential bid.

“Ralph Nader is fouling it all up,” Freeman said. “He’s taking votes away from the Democrats. I think he’s on an ego trip.”

Bush’s job approval in the AP-Ipsos poll was 48 percent, with 49 percent disapproving, which is essentially the same as last month when 47 percent approved of the president’s job performance.

His approval rating, which soared close to 90 percent after the 9-11 terrorist attacks and remained high for months, has dipped to the lowest levels of his presidency in recent weeks.

Six in 10 said the country was on the wrong track, up from last month, while slightly more than a third of those surveyed — 35 percent — said the country was headed in the right direction.

“We’re 240-something days from Election Day. We’ve got a long way to go and expect it to be a close race throughout, no matter what the factors are,” said Terry Holt, a spokesman for the Bush campaign.

The poll was conducted Monday through Wednesday as Kerry captured nine of 10 Super Tuesday elections and claimed the nomination. Nightly results suggested Kerry did not get a bounce from winning the nomination.

Kerry, who had solid backing from 28 percent of the voters, was running strong among minorities, people with low incomes, single people, older voters and Catholics.

Bush, who had solid backing from 37 percent, performed well among whites, men, Protestants, homeowners and suburban dwellers.

“I’m worried about the Democrats taking control,” said Stephanie Rahaniotis, a Republican from Lynbrook, N.Y. She said after the 9-11 attacks, she felt safer with Bush in charge and thinks Democrats will “divert our attention from the military.”

In the poll, Nader was most likely to get the backing of young adults and independents.

The AP-Ipsos poll of 771 registered voters was taken March 1-3 and had a margin of sampling error of plus or minus 3.5 percentage points.