More than two-thirds of Americans—including half of Republicans—still blame former President George W. Bush for the country's economic ills, according to a new Gallup poll released on Thursday, hours before President Barack Obama was to deliver a high-stakes speech defending his handling of the weak economy.

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What one might call the blame gap has narrowed considerably: When Gallup first asked Americans in July 2009 whom they blamed for the poor economy, 80 percent laid a great deal or a moderate amount of blame on Bush, and only 32 percent blamed Obama. The current numbers show 68 percent of the public blames the former president while 52 percent say Obama deserves the blame. (The numbers total more than 100 percent because the question was not "which one do you blame more," but how much blame each president deserves individually.)

The Democratic president has crisscrossed the country in recent months pleading for patience from voters still struggling in the anemic recovery and grappling with stubbornly high unemployment above 8 percent. In his speeches, Obama makes a point of blaming Bush and Republicans in general for the 2007-2008 meltdown and warns that Mitt Romney's economic program resembles the Bush approach "on steroids."

Among independents, who often play a role in deciding elections, 51 percent assign Obama a great deal or a moderate amount of blame, while 47 percent say he deserves not much or no blame at all. Meanwhile, 67 percent of independents say Bush bears a great deal or a moderate amount of the fault. Only 32 percent exonerate him in whole or in part. The survey, conducted June 7-10, includes one eye-popping statistic: While 83 percent of Republicans say Obama deserves a great deal or moderate amount of blame, 49 percent of them believe Bush deserves the same. Democrats are more likely to exonerate Obama. Eight in 10 say he deserves not much or none of the blame, while 9 in 10 say Bush deserves a great deal or a moderate amount. The poll had an error margin of plus or minus 4 percentage points.

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"Americans continue to have more negative than positive views of the current economy and the direction in which it is headed, which generally does not bode well for Obama," Gallup notes.

"Still, 68 percent of Americans say former President Bush should be given a great deal or a moderate amount of blame for the nation's economic woes—substantially more than say the same about Obama. This suggests that Obama's argument that he is on the right track and needs more time to turn the economy around could fall on receptive ears, particularly those of independents," Gallup suggests.