JERUSALEM — During three months of floundering peace talks overshadowed by violence, the American-backed Palestinian leadership in the West Bank has lost popular support and is now viewed as less legitimate than Hamas’ rival Islamist government in the Gaza Strip, according to a poll released yesterday.

The survey is the latest sign that the Bush administration’s effort to shore up secular Palestinian leaders and isolate Hamas is failing. That effort, part of a strategy to stabilize the Middle East, includes diplomatic support and promises of economic aid to the West Bank. Polling data collected in the West Bank and Gaza this month showed that Hamas, which rejects peace talks and continues to fight Israel, has gained sharply in popularity since December, reversing a two-year decline.

The poll was conducted by the Palestinian Center for Policy and Survey Research, an independent think tank that the Bush administration previously has to make the case that its regional strategy was working. According to the poll, Hamas leader Ismail Haniyeh would receive 47% of the vote if the Palestinian Authority held presidential elections today, compared with 46% for the American-backed incumbent, Mahmoud Abbas. The survey group’s polling in December showed Mr. Abbas defeating Mr. Haniyeh in such an election by 56% to 37%.

Mr. Haniyeh was prime minister in a power-sharing government that Mr. Abbas dissolved in June after Hamas gunmen evicted Mr. Abbas’ Fatah-led security forces from Gaza. Mr. Abbas completed the split by appointing a West Bank government led by former World Bank economist Salam Fayyad.