No photographic or video evidence has ever been shown in support.
White House polls taken late this week showed no slippage in support for the President, aides said.
A Newsweek poll showed a modest increase in support, to 58 percent from 53.
Jenin was one of several Palestinian cities where Hamas showed a dramatic growth in electoral support.
Analysis of different polling techniques showed significant differentials in support for Proposition 19.
A poll released Tuesday showed a slide in support for President Bush among members of his party.
Polls show a notable decline since 2004 in support for Republicans among white evangelical Christians, who make up about a quarter of the electorate.
This result showed an increase in support compared to earlier polls.
At the same time, opinion polls showed a rapid decline in support for euro adoption.
Yet the poll also showed a decline in support, from a 75 percent approval rating in February 2000.