Washington ? President Bush’s re-election team drove up negative impressions of John Kerry during a relentless $80 million advertising campaign the past three months, but the Republicans failed to undercut the Democrat’s standing as a viable alternative to Bush.

As the Bush-Cheney campaign’s spring push draws to a close, the Republicans have succeeded in changing voters’ perception of Kerry — from a positive opinion held by a majority of Americans to a largely divided view.

After winning the primaries in early March, Kerry was viewed favorably by a 2-to-1 margin. Now, half view him favorably and four in 10 have an unfavorable view, according to a Pew Research Center poll this week.

“The Bush campaign raised Kerry’s negatives on the themes they were advertising and reinforced the perception of Bush as a strong leader,” said Kathleen Hall Jamieson, a specialist in political communication and director of the Annenberg Public Policy Center at the University of Pennsylvania.

A majority of voters critical of Kerry are more likely to mention his character as a major reason, especially his perceived inconsistency on issues, the poll found. The Democrat didn’t help his cause with a handful of campaign slips, including an odd explanation that the GOP incorporated into the Bush ads.

During a West Virginia campaign stop, Kerry said he voted for the $87 billion aid package for Afghanistan and Iraq before voting against it — a clumsy attempt to answer Bush’s criticism that he hadn’t supported the troops. Kerry had favored an earlier version that called for rescinding tax cuts to pay for the bill; when that failed, he cast a protest vote that would have no impact on the bill’s passage.

Although the Bush re-election campaign has achieved one goal — changing voters’ views of the Democrat — it has been unable to do what President Clinton managed in 1996: open what proved to be an insurmountable lead over Republican Bob Dole.

Eight years ago, the Clinton re-election team, relying on an aggressive ad campaign, turned a 4 percentage-point lead over Dole in January into a 16-point advantage in June. Recent surveys show Kerry either tied with Bush or one candidate holding a slight advantage over the other.