The latest Pew Research Center poll shows President Bush ahead of John Kerry by eight points.

Two successive nationwide surveys of nearly 1,000 registered voters each show Bush’s margin over Kerry growing steadily since mid-September (Sept. 11-14), when the two men were tied at 6%-46%. Bush’s slight 45%-42% advantage in the Sept. 17-21 survey has grown to 48%-40% in the current poll (Sept. 22-26).

The poll finds that Bush’s gains in support are being driven more by perceptions of Kerry’s weakness especially on leadership and other personal traits than by improved opinions of Bush. Fewer voters favor Bush over Kerry on handling Iraq than did so earlier this month (46% now, 52% Sept. 11-13). But Kerry’s rating in the head-to-head evaluation on Iraq is no higher (38% now, 40% then). The Democratic challenger continues to inspire more confidence than Bush with regard to improving the economy, which 60% of Americans believe is in only fair or poor shape. But even here, the percentage favoring Kerry has not increased since the Sept. 11-13 survey (46% now, 47% then). …

Kerry’s image weakness is most evident on questions of leadership and his willingness to take on unpopular positions. Just 28% say the phrase “strong leader” better fits Kerry, virtually unchanged from earlier this month, while 54% say it applies to Bush. And 23% believe Kerry takes on unpopular stances, compared with 63% who say that about Bush. In both cases, Bush’s ratings are down slightly from earlier this month, but Kerry has gained no ground.